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Comment by ulrikrasmussen | Hacker News Reader

You seem to know a lot more about this than me, so pardon my ignorance, but how come cruising at low altitude is more economical with an electric plane? I thought that the primary reason for wanting to go high was because of the decreased air density and thus resistance, and I reckon that that would not change for an electric plane. Is it just because the energy is cheaper so the extra overhead is less significant?

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Probably because fuel is so much more expensive than electricity.

You avoid having to climb all the way up just so you're using up less of this very expensive fuel, which especially on short haul flights is a huge % of the whole flight.

Not actually economical in terms of energy used per distance covered, but more practical and likely to be appreciated by passengers? Less stress on the airframe too, probably.

Noise could be an issue too— no one wants a passenger jet flying over their city at <5000ft, but maybe it wouldn't such a big issue if it was a lot quieter.

Because he/she doesn't know what he's talking about. Jets will always cruise at their maximum allowed altitude except for some really short flights. In cruise the only thing you're fighting is aerodynamic drag (no ground friction) and climbing is the best way to reduce that.

If anything electric planes using their higher thrust will even climb quicker.

For short haul what matters is balancing how much energy is spent getting up high vs. how much benefit you are getting from being there. With an electrical engine you'll go as high as needed to maximize your range. The energy cost is not really a consideration here, it's all about the range.

With a jet you will instead be optimizing fuel flow since that fundamentally drives your cost. That means taking the minimum amount of fuel you can get away with and the maximum number of passengers to ensure you actually recover the cost of the fuel you are burning.

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