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Comment by dude250711 | Hacker News Reader

Better for the planet though.

Don't think so. The people will still need to fly and incidents like these mean lots of planes are out of place and may need to fly extra to reposition

most flights are not necessary

Define "necessary". Good luck.

the flight doesn't contribute to preventing harm to anyone

It's not uncommon to travel for medical care, or for medics to travel for work.

If you set traveling and flying equal, I very much think it is.

The US has a bunch of highly paid medics who fly every week or in some cases every day because they work somewhere with enough population to justify their practice but they choose to live somewhere hundreds of miles away, and at their income it's actually practical to have a small private jet. It's probably only a small minority of the most highly paid (so e.g. cosmetic surgeons) where this makes sense but it's more than a handful of people.

Likewise because it's big and a lot of it is empty the US does more medical flights than a country like the UK, if a Wyoming multi-millionaire needs urgent treatment in a Californian hospital you're not going to load him into a truck and drive there, you use a plane. This is relatively high risk commercial air travel, it's not quite as dangerous as most GA but there's some get-there-itis because you don't want to abort the flight and let down your patient, and you're often flying one-off journeys whereas the people doing scheduled passenger travel it's like a bus, same route, every time, regular as clockwork, and if things go wrong you just scratch the flight and no harm, no foul.

No, it's as I said.

There was a famous case in 2017 where a surgeon was violently removed from an overbooked United Express airliner. He had refused to leave voluntarily, as doing so would have meant not seeing his patients the next day. [0] I'm not sure this strictly counts as travelling for work, but the points remains.

Plenty of people fly abroad for medical care. [1]

Over 2,000 flights were cancelled in this incident. Over 300,000 would-be passengers were affected. [2] It's implausible that nobody's medical care was affected.

[0] https://en.wikipedia.org/wiki/2017_United_Express_passenger_...

[1] https://en.wikipedia.org/wiki/Medical_tourism

[2] https://aerospaceglobalnews.com/news/uk-airport-disruption-f...

I did not claim nobody's medical care was affected.

It could have happened if it was uncommon and it could have happened if it is common.

My claims:

1) most flight's are not necessary

2) it's not common to fly for medical care (yes, very rich people may have a different perception, but that's all it is)

> I did not claim nobody's medical care was affected.

You said the flight doesn't contribute to preventing harm to anyone. Interfering with medical care is a clear form of harm, that's why I focused on it.

> it's not common to fly for medical care (yes, very rich people may have a different perception, but that's all it is)

That's incorrect on both counts: it's common, and it's not just rich patients. Please take a look at the Medical tourism Wikipedia article I linked above. Cost-reduction is a major motivation of medical tourism.

From [0] :

> in 2016 nearly 144,000 UK citizens travelled abroad for medical treatment. The survey suggests a steady increase since 2000, even though the 2016 sample of 250,000 travellers represent 0.23% of the total number of travellers entering or leaving the UK.

See also [1].

[0] https://doi.org/10.58248/PB38 Outward medical tourism (2020)

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC3812100/ Medical Tourism: A Cost or Benefit to the NHS? (2013)

That is a super weird definition. If you only want to allow that you're going to have to ban basically everything.

not everything is as harmful as flying

Who knows. Maybe someone will decide to compensate with 2 flights instead of one.

Ocean liners use several times more fuel per passenger mile than airliners.

Thats a bit of an odd comparison as they are in pretty different categories and don’t really compete against each other.

They don't in this case, because there's plenty of other airlines offering competing service, but when disruptions do prevent air travel, for example with the eruption of Eyjafjallajökull, travelers cruising to their destination will burn far more fuel.

Granted, the difference in emissions of either form of traveling are absolutely nothing compared to the emissions of Eyjafjallajökull itself.

The speed of the ship makes a huge difference in fuel consumption. Cruise ships/ocean liners usually go as fast as practicable, which leads to terrible fuel efficiency. Reducing speed from 20 knots to 15 knots may cut fuel consumption in half or more.

One thing I’ve noticed is that a lot of comparisons you’ll see will have, for example, a 5-day journey by cruise ship compared with an airline flight covering the same distance. Usually measured not in fuel consumed but carbon emissions. Ok, but shouldn’t the more accurate comparison be a 5-day cruise compared to an airplane trip plus 5 days in a hotel?

I once bought an overnight train ticket from France to Italy, instead of spending more on a high-speed train ticket and a hotel night. It would have been a great idea, if the train didn't have its heater stuck on, in August, and a broken emergency pull cord in an unknown car, which resulted in multiple unintended stops that required the staff enter every cabin to reset the pull cords, before resuming. I learned to check the reputation of the train line, like I would a hotel.

Anyway, traveling efficiency is a factor of the speed and size of the vessel and the viscosity of what it's traveling through. It's non-linear, and scaling up the vessel size slowly adds efficiency, and speeding up the vehicle or increasing the viscosity quickly reduces efficiency.

Boats have an advantage by getting very big, but a really, really big disadvantage if they go fast, which is why huge boats going slow is their most common use, mostly for cargo, but sometimes for people, when the ship itself can be a destination. Trains can't get very big, but air is much less viscous than water, so they can go a few times faster without major losses. This is why rail is really popular for transporting cargo across the US and Canada, although it's not fast enough for long distance passenger travel.

The absolute peak in energy efficiency comes from a large vessel moving through a very-low viscosity atmosphere, which is what airliners are able to do, by traveling in the stratosphere, eliminating the majority of the drag, and allowing for effectively uncapped speeds. Really, the faster an airplane can travel, the higher it can go, further reducing drag and increasing efficiency. The limit is technological, not physical, but current airplanes traveling around mach 0.8 get very high cruise efficiency from both being large and being in a low-viscosity atmosphere.

Ocean liners use several times more fuel per passenger mile than airliners.

So what? Two things can be bad at the same time. Nobody mentioned ocean liners except you. Why not bring up the greenhouse gases from landfills while you're at it?

Whatabouting everything is so last decade.

Calling everything "whatabouting" when someone is just responding and expanding context to an existing comparison is what's actually last decade.

Last decade is so last decade

There is exactly one actual ocean liner left, QM2 which goes between my home city and New York. Most of the ships you're thinking of are Cruise liners, which are not in fact (unlike an airliner or ocean liner) designed to prioritize travel but are instead floating hotels which might happen to travel from one place to another.

What's the alternative?

Really often the alternative was not to make the journey. Whether that's the in-person visit to a customer site which could have been a video call (or an email) or the trip to go see how your Porsche was made in the factory.

WG21 (the C++ Standards Committee) only began to allow you to present proposals or attend committee meetings without flying around the world in... 2020 because of Pandemic restrictions.

Video conferencing was one of the technologies in Engelbart's "Mother of all demos" in 1968. Remember that year, not 2008, not even 1998, it was demonstrated in 1968 and yet I bet several readers of this comment have flown on an aeroplane to do something they could have done using video conferencing, almost sixty years later. What a joke.

Oh, of course, but I mean for moving people who want to move around. Someone else observed that ocean liners are less efficient than planes, so if you wanna go overseas there's no alternative.

Except, of course, for business meetings which can be virtual (or just an email). I'm asking what's a practical alternative assuming we still want people to be able to go overseas. I agree for land routes high speed rail is better, too. I don't really understand my downvotes just for asking about alternatives.

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