[shanewilhelm]

Pure speculation on my part, but maybe that's better for the environment because it's not being burned as it's used?

[coin]

Make the airplane light for landing. Many large aircraft takeoff heavier than their max landing weight.

[qbrass]

They burned twice that much fuel getting the plane into the air, flying an hour and a half, then having to turn back.

[extraduder_ire]

It'll turn into CO2 eventually. For now, it's just contributing to smog.