> Doesn't really matter what it exhausts, it expends energy either way. Energy usage is not the only consideration, and it certainly does matter what it exhaus

> Doesn't really matter what it exhausts, it expends energy either way. Energy usage is not the only consideration, and it certainly does matter what it exhausts. Exhausting an inert gas is definitely preferable to a greenhouse gas, which would be preferable to exhausting anthrax, etc. The composition of the exhaust is going to affect the positivity of the public reaction to a billionaire burning it into public air space for leisure.