[riazrizvi]

Reserve fuel? I didn’t even allocate any fuel to land, I am assuming passengers won’t mind the bumps at their destination, you know for the planet.

[catalogia]

There are more practical ways to reduce the population than cratering airplanes into runways.

Fuel is a major expense for commercial airlines, they don't burn it just for shits and giggles. Airplanes use fuel when landing because destroyed aircraft and piles of corpses will quickly cost more than any fuel they'd save by trying to glide every plane to the ground.