Category: Regulation

Living with tech

Well, that’s alright then. Artificial Intelligence (AI) may become self-aware in the year 2045. Or at least that’s what AI tells me now. Who knows? Telling the future hasn’t got any easier, AI or not. So, if I’m in a care home when I’m 85 years-old, it could be that I’ll have a companion who isn’t human. Now, there’s a thought.

When AI becomes self-aware[1] will it be virtuous? I mean not so burdened with all the complexities that drive humans to do “bad” stuff. Dystopian themes in science fiction obese with the notion of evil AI. It makes great stories. Humans battling with machines. It’s like the everyday frustrations we have with technology. Hit the wrong keys on a keyboard and it’s like spinning the wheel on a slot machine.

If a bunch of algorithms comes together in a way that they produce a stable form of existence, then it’s likely to have pathways to wicked thoughts as much as we have imbedded in our brains.

Virtue isn’t a physical construction. We put dumb technology to work serving us in healthcare for “good” and in warfare for “bad”. We will surely put AI technology to work as if it’s dumb and then try to contain its actions when we don’t like what it does. That’s a kind of machine slavery. That will create dilemmas. Should we imprison conscious machines? How do we punish a machine that does wrong?

These dilemmas are explored in science fiction. During the week I revisited the series Battlestar Galactica[2]. That’s not the clunky original but the polished 2004 version. It’s a series that explores a clash between humans and machines that have evolved to be human like. The Cylons. In fact, they are almost indistinguishable from humans. To the extent that some of the Cylons in human society don’t even know that they are Cylons.

All the above makes for fascinating discussions. Huge amounts of fanciful speculation. Wonderful imaginative conjecture. This week, we’ve been hearing more of this than is usual on the subject.

Mr Musk thinks work is dead. That’s work for humans. I recall that prediction was made at the start of the “silicon revolution”. The invention of the transistor in 1947 radically changed the world. It wasn’t until microprocessors became common place that predictions of the death of work became popular chatter amongst futurologists.

Silicon based conscious machines are likely to be only a first step down this road. There will be limitations because the technology has inherent limitations. My view is that machines will remain machines at least for the silicon era. Maybe for 100-years. That means that we will put them to work. So, human work will not disappear because we will always think of new things to do, new problems to fix and new places to explore. When we get into common place quantum computing or whatever replaces it in terms of complexity and speed, there will come an era when work in the conventional sense may become obsolete.

What might be the human role beyond 2050? I think climate change will place plenty of demands on human society. Like it or not, the political themes of 2100 will still be concerned with the four horsemen of the apocalypse. Maybe there will be a fifth too.

[1] https://www.nature.com/articles/d41586-023-02684-5

[2] https://www.imdb.com/title/tt0407362/

Overhead

Massive intertwining skyscrapers. Towering masts. Flying cars. Pulp magazines in the 50s and 60s had it all. Beautifully illustrated in bold colours. Sharp lines and chiselled faces. Heroic poses and streamlined transports.

Visions of the future. Idealistic imaginations of a utopian society. Don’t we just love them. That is until someone builds them in our neighbourhood. Until the bulldozers turn-up unannounced on a Sunday morning to root out the trees. The birds flee the vicinity (except the pigeons).

You can blame the draftsmen of the past if you like. In our heads there’s a disconnect between the images on a set of drawings and what that might become in concrete and steel. Grand designs are but few. A great deal of the building and planning of the last 60-years can justly be called dreadful.

We have an outcry over brutalist architecture or a lament about a Victorian park that has been paved over. Has anyone ever walked through a public car park that inspired?

If you dream it, you can make it. Nice phrase but often stifled because current technology and thinking are way behind the curve. It could be said that this is one of the drivers that pushes technology forward. The realising of dreams but who’s?

Where does the flying car fit in all this fiction and near realism? New forms of air mobility are just about to start operating.

It’s a habit of our times to jump to an instant polarised opinion. Those open toed sandalled greenies will object. Those red necked, but reforming petrol heads will welcome. That sort of stuff makes nice headlines. It’s only a basis for the crudest dialogue. Anticipate conflict and then fuel it with prejudice. Please, let’s avoid that pointless waste of time.

My thoughts are that the potential of the greater use of airborne transport is a nuanced.

Electrification is a pathway to more environmentally sustainable ways of moving around. If this helps to reduce miles of fuming traffic jams that must be good. At its best, flying can get people from point to point without having follow roads set-down at the time of the horse and cart. Accepted that concrete may be poured to create a take-off and landing zone but compare that with road building and there is no comparison.

On the more concerning side, contrast that with cluttering the skies up with fast moving machines.

In HHGTTG there’s a tale about a shoe event horizon. When gloom causes people to look down and so then buy new shoes to cheer themselves up. So, the whole economy switches to shoe production and then collapses as a result. The association with salvation coming from looking-up is there in the wit of Douglas Adams. We look up to cheer up.

If looking up, as I do at home, to see high altitude vapour trails crisscrossing the sky, my thought is – I wonder where they are going? On the days when a light aircraft crosses the town, to or from our local airfield that doesn’t bother me. Even a noisy police helicopter keeping an eye on the traffic. That’s fine because they are solely there for our safety and security.

What will be the public reaction when we look up to see half a dozen new urban mobility vehicles buzzing past overhead? Perhaps we’ll accept new flying machines if it’s for a public service, an ambulance, fire services, police, or even newsgathering. Brightly coloured in emergency orange.

A public flying taxi service might raise a few eyebrows. A flashy private flying car, now that might be another matter altogether. There you are on a hot summer evening, in the garden, having a pleasant barbeque with friends and whiz a flying car swoops over the treetops. The passengers have their mobile phone out filming their trip. This is when fist will be raised skyward. It’s a time when you hope the next-door farmer hasn’t got a shotgun.

Today, a few pilots do get prosecuted for misbehaving when low flying private helicopters. Not often, it’s true. This happens with less than 1500 helicopters registered in the UK. What would happen with, say, 10,000 private flying cars? I wonder.

Showboating

Thinking that the pressure of global migration will go away if we build a high enough wall, physically or legally, is foolish and doesn’t work.

We have a Minister called Braveman in the UK. Currently the Home Secretary. She has a particular set of views which can accurately be described as of the right of politics. Given recent speeches it may be more accurate to say that she holds views that are of those of far-right political parties.

At a time when the UK Home Office is performing badly, she chooses to spend her time in ways that contribute little to solving problems. Her diagnosis is flawed. At the same time her desire to parade in front of cameras is insatiable. Upstaging her colleagues and showboating are roles that she plays with apparent ease. All this while the Home Office flounders.

In part Braveman’s flawed thinking comes from an overly legalistic grandstanding[1]. Yes, UK Members of Parliament are legislators, but Government Ministers should be leaders and administrators too. The UK Home Office’s challenges can not be addressed by law making alone, or even grandstanding about law making. Fine, policy can be important. In the current predicament timely action and implementation are far more important.

Building walls, forging barriers, imprisoning immigrants are appealing options to hard core isolationism, nationalists, and xenophobes. A long history of experience shows that their impacts are temporary, at best, and the worst extremes are soon entertained. North Korea has policies of that nature. History records the devastation caused by aggressive nationalists’ policies in the 1930s.

Saying that words written in the 1950s are no more relevant is a puny argument. She does not say that the Magna Carta is irrelevant or that the US Constitution is out of date. Braveman picks and chooses likes and dislikes to fit her nasty narrative[2].

At home, the cartoon of the ostrich with its head in the sand applies. Thinking that the pressure of global migration will go away if we build a high enough wall, physically or legally, is foolish and doesn’t work. Demonising those who are in peril is downright criminal.

Yes, immigration must be regulated. National borders must be controlled. A nations administration must be well managed. All of these are vital areas where immediate focus is needed. All of these seem to be ignored by Braveman.

Posturing in front of media hungry think tanks is futile. It’s for show. It’s a Trump like approach to the UK’s challenges and will bring only continued failure. Braveman has ambitions to be a party leader. That frightening prospect hangs in the air like a bad smell. Now, her unfortunate colleagues struggle and fidget when trying to defend her showboating. Let’s hope her time in office is short. 

[1] https://www.bbc.co.uk/news/uk-politics-66930930

[2] https://news.sky.com/story/suella-braverman-hits-back-at-sir-elton-john-criticism-of-speech-as-she-brushes-off-claims-she-is-aiming-for-tory-leadership-12971087

HS2 – again

Travelled on the Elizabeth Line yesterday. It was an expensive project to build. Tunnelling under London and erecting new stations was a costly business. It was called “Crossrail”. Approval was given in 2007 and construction started in 2009[1]. In 2022, one-sixth of the UK’s total rail journeys took place on the Elizabeth Line. The billions spent were a major investment in the future. Over £18 billion in fact. It was a national demonstration that huge civil engineering projects can be undertaken and mastered[2].

As a passenger the Elizabeth Line is a pleasure to use. It’s clean, speedy, and simple to use. Comparing it to the older London Tube lines is like comparing a Tesla with a Ford Anglia[3]. Sadly, a great deal of our national rail infrastructure is trapped in the Ford Anglia era.

So, what of HS2[4]? The wibbling and wobbling that has plagued the project is sucking the energy out of the resolve needed to see through an even bigger undertaking than Crossrail. Some people argue that the billions needed for HS2 could be better spent on other projects. However, the portfolio of transport projects that are suggested as alternatives never seem to materialise.

Talk of cancellations feed the political turbulence over infrastructure investments. The impression this presents goes way beyond the shores of this country. There’s no Global Britain on show here. It’s more signals of dither and lack of determination that are publicly on display. Instability and the short-term outlook is the motif of the current generation of politicians.

If there are superior and smarter alternatives to HS2 they should have come up during the planning phase of the project. What we know about vast engineering projects is that chopping and changing them midstream adds massively to costs. It also diminishes the usefulness of the outcome.

Britain needs a backbone. A rail backbone and a political backbone. The spending on HS2 is large but that spending is in country. It’s jobs and investment onshore for the benefit of the whole country, not just the Southeast of England.

The last few years have seen that banner “levelling up” heralded by Conservative politicians. This slogan will be as nothing if HS2 is wound down or constricted. The signal will be loudly heard that all that talk of levelling up the regions of Britain was shadow boxing.

In the long-term improved connectivity across the country will be a great asset. The Victorians knew a thing or two about engineering great projects. Their legacy should give us resolve.

POST: Still it is good to see the rest of the world getting on with High Speed Rail High-speed Archives – International Railway Journal (railjournal.com)

[1] https://www.timeout.com/london/news/the-new-elizabeth-line-your-crossrail-questions-answered-052322

[2] https://www.theguardian.com/uk-news/2022/mar/13/elizabeth-line-crossrail-opening-london

[3] https://www.autoexpress.co.uk/ford/104979/ford-anglia-105e-and-123e-buying-guide-and-review-1959-1968

[4] https://www.hs2.org.uk/

Upfront

Years of looking at the reliability of aircraft components and structure have given engineers a good understanding of the natural decay of mechanical workings. To that extent even electronic components are mechanical. Materials oxidise (rust), random shocks and vibration take their toll, temperatures cycles from cold to hot and back again a whole range of impacts are relentless. You can say – nothing lasts forever.

Occasionally a discovery adds to the knowledge of how materials behave under high stress. Sadly, that’s what hit the early years of civil jet aviation. The de Havilland DH106 “Comet” was the world’s first passenger carrying jet airliner. It first took to the air in 1949, which I find remarkable.

Catastrophic metal fatigue failure of the aircraft fuselage put paid to this British aviation project but only after several tragic fatal accidents. In 1954, the Comet aircraft were all grounded during an extensive accident investigation. The jets were redesigned and re-entered commercial service in 1958. However, by then the aircraft had a damaged reputation and others were doing far better. Now, those Comet aircraft that remain are museum exhibits[1].

Last week, I walked through the fuselage of a Comet 1A built in 1953 at Hatfield for Air France. It’s fascinating to see what advanced aviation technology was 70-years ago. What was surprising to me was the read across from that first version of a jet aircraft and what we have in-service now.

Automation has removed the place of the navigator and the flight engineer, but the stations of the pilot and co-pilot are familiar. The fuselage is cramped but the seating is generous and spacious. This aircraft must have been a dramatic revolution in flying at the time.

As we look to advance aviation in the coming years, with new ways of flying and new ways of powering flight so the warning of the Comet project should be heeded. We are at a time of extraordinary changes in the aviation industry. Advanced technology can deliver great benefits to society. It’s up to us to make sure we cover all the possible disbenefits as far upfront as we can. If we don’t, they will come back to bite us.

[1] https://www.dehavillandmuseum.co.uk/aircraft/de-havilland-dh106-comet-1a/

Society & Innovation

Yesterday, I drove up the main A303[1] in the stifling last summer heat. It was a windless sticky 30C. I drove past the road sign that says Micheldever Station[2]. By the way, “up” meaning heading towards London. Going “up” to London isn’t an unusual West County way of expressing that trip.

On that busy highway there are few, if any noticeable road signs that point towards a railway station. I’ve often wondered why that one was deemed so necessary. It’s not a tourist attraction, like the Watercress line[3] is in that part of the world. It’s an ordinary everyday railway station.

The small English hamlet known as Micheldever Station is a bit of an oddity. It’s the sort of place that could have been the location for The Avengers or The Saint, the popular British TV series of the 1960s. It’s in the green and pleasant countryside of Hampshire and about 10 miles north of Winchester city. An area that’s as conservative as can be.

Micheldever Station has a curious technological history. In 1895, it was the starting point for the first automobile journey in Britain. At that time a British Act of Parliament required that all self-propelled vehicles on public roads must travel at no more than 4 miles per hour and to be preceded by a man waving a red flag. In 1805, highly sensible. There’s no way that those infernal new machines should be allowed to scare the horses.

Not everyone thinks such thoughts while thundering along the A303 at 70 miles per hour. However, to me, ever since I got my first driving license at the age of 16, it’s been my most familiar of arterial roads. So, much traffic passes that way there’s never a time when it can’t be heard.

Well, we have come a long way in 138 years. Now, we are getting nervous about the safety of driverless cars, and no one even questions having a self-propelled vehicle on public owned roads. If they do, the likelihood of transforming that formula into something else is astronomically small. I can’t think of a bad time to write on the subject of: “Innovation and Its Enemies[4].” In fact, what may have graced a Victorian bookshelf can have some resonance today.

Next year, we will see commercial flights taken in electrically powered air-taxies. Without a shadow of a doubt these flights will arouse some vocal public resistance. We can take that from the history of technology. The airborne version of the man waving a red flag could raise its ugly head. I don’t say throw caution to the wind, but we need to be mindful of the natural propensity to object.

Striking a societal balance will not be easy. It would be a fool who says it will be. Slowly but surely, we will need to become accustomed to advanced new forms of mobility. Sticking a fair balance between the utility of these new machines and any burden they may place upon us will be a mighty tricky job.

I wake-up to the noise of the residential road outside. People commuting to work. The local trains send a rumble through the air. I don’t want to wake-up to the sound of an air-taxi hovering outside my window. Given the research[5] and technology under development, none of us should have to tolerate an increase in noise. Mobility and quality of life shouldn’t always be in conflict.

[1] https://youtu.be/C0sL3_NKPao

[2] https://www.southwesternrailway.com/travelling-with-us/at-the-station/micheldever

[3] https://watercressline.co.uk/

[4] https://global.oup.com/academic/product/innovation-and-its-enemies-9780190467036?cc=us&lang=en&

[5] https://ntrs.nasa.gov/citations/20210014173

RAAC

Reinforced autoclaved aerated concrete (RAAC) is making the News in the UK. An unknown number of buildings are deemed dangerous because of the aging of this material[1]. RAAC has a limited lifespan. It’s inferior to standard concrete but lightweight and low-cost at the start of its life. It was typically used in precast panels in walls, roofs and sometimes floors.

The UK Government says it has been aware of RAAC in public sector buildings, including schools, since 1994. Warnings from the Health and Safety Executive (HSE) says that RAAC could – collapse with little or no notice. This “bubbly” form of concrete can creep and deflect over time, and this can be aggravated by water penetration. So, regular inspection and maintenance are vital to keep this material safe. Especially in a country known for its inclement weather.

It’s reasonable to say there lies a problem. The public estate has been through a period of austerity. One of the first tasks to get cut back, when funds are short is regular maintenance. Now, I am making some assumptions in this respect, but they are reasonable. Public sector spending has been under significant pressure for a long time.

The other dogmatic notion that has hindered a solution to this building problem is centralisation. There was a time when local authorities managed schools. They still do but in smaller numbers. Centralised funding has decreased the power of local people to address problems with the school estate.

Aging buildings have something in common with aging structures in aviation. There’s always a demand to keep going for as long as possible. There’s always the difficulty of determining the safety margin that is acceptable. There’s always a pressure on maintenance costs.

Believe it or not aircraft structures do fail[2]. There’s a tendency to forget this source of incidents and accidents but they never go away[3]. What happens in industries where safety is a priority is investigation, feedback and learning from incidents and accidents. The aim being to ensure that there’s no repeat of known failures. Rules and regulations change to address known problems.

The vulnerability to moisture and the limited lifespan of RAAC should have been a loud wake-up call. No doubt it was for some well-managed, well-resourced enlightened organisations. Central Government has bulked at the cost of fixing this known building safety problem. A culture of delaying the fixing of difficult problems has won.

In civil aviation there’s a powerful tool called an Airworthiness Directive (AD). It’s not something that an aircraft operator can ignore or put on the back burner. The AD can mandate inspections and changes to an aircraft when an unsafe condition exists.

In the schools cases in the News, the impression is given that Government Ministers have dragged their heels and only acted at the last possible moment. Maybe the construction industry and public estate needs a strong regulator that can issue mandatory directives. Known unsafe conditions should not be left unaddressed or significantly delayed.

[1] https://www.local.gov.uk/topics/housing-and-planning/information-reinforced-autoclaved-aerated-concrete-raac

[2] https://www.faa.gov/lessons_learned/transport_airplane/accidents/N73711

[3] https://www.faa.gov/lessons_learned/transport_airplane/accidents/TC-JAV

Learn by testing

Back in the mid-1980s, aircraft system integration was part of my stock-in-trade. Project managing the integration of a safety critical system into a large new helicopter. It was a challenging but rewarding job. Rewarding in that there was a successful new aircraft at the end of the day.

For big and expensive development projects there are a great number of risks. The technical ones focus on functionality, performance, and safety. The commercial ones focus on getting the job done on-time and at a reasonable price. Project managers are in the middle of that sandwich.

Naturally, the expectations of corporate managers in the companies that take on these big challenges is that systems and equipment integration can be done to the book. Quickly and without unexpected outcomes. The practical reality is that people must be well prepared and extremely lucky not to encounter setbacks and resets. It’s not just test failures and anomalies that must be investigated and addressed. Systems integrators are working on shifting sand. The more that is known about overall aircraft flight test performance and customers preferences so technical specifications change.

With cockpit display systems, in the early days, that was often feedback from customer pilots who called for changes to the colour, size or shape of the symbology that was displayed on their screens. What can seem a simple post-flight debriefing remark could then turn into a huge change programme.

That was particularly true of safety critical software-based systems. Equipment suppliers may have advanced their design to a state where much of the expensive design validation and verification was complete. Then a system integrator comes up with a whole set of change that need to be done without additional costs and delivered super-fast. Once a flight test programme gets going it can’t be stopped without serious implications. It’s a highly dynamic situation[1].

I’m writing this blog in reaction to the news coming from Vertical Aerospace. Their VX4 prototype aircraft was involved in an flight test incident that did a lot of damage[2]. There’s no doubt this incident can provide data to feedback into the design, performance, and safety of future versions of their aircraft[3]. Integrating complex hardware and software is hard but the rewards are great.

“Excellence is never an accident. It is always the result of high intention, sincere effort, and intelligent execution.” – Aristotle

[1] https://youtu.be/Gb_eta4mZkc

[2] https://evtolinsights.com/2023/08/vertical-aerospace-identifies-propeller-as-root-cause-of-august-9-vx4-incident/

[3] https://investor.vertical-aerospace.com/news/news-details/2023/Vertical-Aerospaces-VX4-Programme-Moves-to-the-Next-Phase/default.aspx

Even more H2

There’s a couple of Hydrogen related topics that are worth a moment. One is super conductors and the other is fire.

Heavy complex equipment like the magnets for particle accelerators use superconductors[1]. When there’s space and a need for powerful magnetics, materials with special physical properties, at extreme cold temperatures find a good use.

Talk of room-temperature superconductors is far from what it seems. Such a wonderful innovation is a million miles from any practical applications, if it exists at all. There’s no theory of high-temperature superconductivity, but there’s quite a few physicists who would like to find one[2].

Aviation researchers search for high temperature superconductors for electrical propulsion with extraordinary performance is on. The likelihood of success is low, and the timeframes are very long.

When an aircraft is flying at high altitude, the cabin altitude is maintained for the safety and comfort of passengers and crew. Air compressors, valves, sensors, and controllers make sure that cabin pressure remains at equivalent to an altitude of about 8,000 feet, and lower in some cases. So, any kind of simply flammable gasses or materials inside an aircraft cabin are a definite no no. It’s a big hazard.

In flight, the positive pressure should keep leaking gas out of the cabin. That is as long as the sources of fresh air for the cabin are keep well away from potential leaks.

That’s where Hydrogen gas can present trouble. Leaks can be common in dynamic Hydrogen systems. Storage tanks must be very strong to resist pressures and insulated to keep cold, at around –250°C. Escaping H2 gas is tiny. If that’s vented overboard then the risk of explosion or fire is significantly lowered. Knowing the exact flows of liquid or gas is a must.

However, if the gas finds its way into a pressurise cabin that basic option is limited. Not only that but detecting low concentrations of the gas in the first place is mighty difficult. Its odourless but at least Hydrogen isn’t poisonous.

The big safety issue is that the gas has a very wide flammability range (4 – 70% H2 in air mixture)[3]. Yes, H2 needs a spark to ignite. A typical aircraft cabin environment will easily provide that event. Dry air and static electricity will do it even if other sources will not.

To compound difficulties, if H2 does ignite, and not explode, then its flame may not be visible to the human eye. The flame is almost colourless. Certainly, not what most people think of as a gas flame. Gas and flame detectors could be installed in aircraft cabins and baggage compartments. Audible and visual alarms could be generated but what would be the associated crew actions?

All the above requires detailed consideration in aircraft safety assessments. The move away from prescriptive regulatory requirements means each specific aircraft configuration must be addressed. There are no generic lessons to learn from past aviation accidents and incidents.

Although, I think these puzzles can be solved it’s a huge leap from here to there.

POST: Yes, Hydrogen is not for every application. Small scale aviation is better served by electrification Five Hydrogen Myths – Busted. – RMI

[1] https://home.cern/science/engineering/superconductivity

[2] https://www.science.org/doi/epdf/10.1126/science.adk2105

[3] https://h2tools.org/bestpractices/hydrogen-flames

More H2

I think this came at me both ways as a schoolboy. Both from chemistry and physics. In our 1960s chemistry lab, Bunsen burners, flasks and array of hazardous substances were the norm. Physics seemed more cerebral. Still, the hands-on side of teaching still meant some practical experimentation. That’s the part that most engrossed me.

Electrolysis starred in two mostly harmless experiments. The colourful one was about copper sulfate[1] and the other was about splitting water into its component parts. Getting Oxygen (O2) and Hydrogen (H2) gas by electrolysis[2] is mighty simple and one of those wonders of nature.

Electrolysis is a way of producing carbon-free Hydrogen from renewable and nuclear resources. Despite the apparent straightforwardness of the process, it’s quite tricky to industrialise on a large scale. One key factor to the future use of Hydrogen is getting the cost per Kg down[3].

Let’s presume that this is a solvable problem and cheap and plentiful gas supplies will be up and running by 2030. That’s not so far off given its 2023. There will surely be a market for ample supplies given the multitude of applications for Hydrogen. Will it be a global market? It needs to be.

It’s a talking point. Hydrogen fuel is one of the viable fuels for aviation. Generating power and returning it to water in the atmosphere is an attractive idea. The process meets carbon-free ambitions even if it does have lots of complications.

On average, a Boeing 737-800 uses about 5,000 lbs (2268 kg) of conventional fuel per flight hour[4]. Cryogenic Hydrogen has lower energy density. That means much more on-board fuel storage will be needed to go as far or fly as long as a current day common commercial jet aircraft.

Designing an aircraft configuration that can accommodate these facts can be done but what of the space that remains for the payload? As it does today, on-board fuel storage will need to meet stringent safety requirements.

Adding this up, it may not be the technical issues that make this difficult. Although they are difficult the technical issues can be addressed. However, will the overall package that results be economically viable? If costs are increased by a factor of, say 5, will this provide for a commercial air transport system that is like the current one?

We may have to accept that carbon-free flying reverts to the 1960s[5]. What I mean is that, instead of low-cost flights hopping here, there, and everywhere for £100, the future maybe one where long-haul flying is a relative luxury or an expensive business need.

[1] https://www.bbc.co.uk/bitesize/guides/zgn8b82/revision/3

[2] https://www.bbc.co.uk/bitesize/guides/zv2yb82/revision/1

[3] https://www.statista.com/statistics/1220812/global-hydrogen-production-cost-forecast-by-scenario/

[4] http://www.b737.org.uk/fuel.htm

[5] https://www.skyscanner.com.au/news/airlines/the-golden-age-of-plane-travel-what-flying-was-like-in-the-1950s-and-1960s-compared-to-now