system
Given the following post, respond as if you're commenting on Reddit:
human
Why do large airplanes retract their landing gear after taking off?

Recently there have been a handful of instances in which a plane had to be landed with landing gear that was stuck retracted. I am curious as to whether the benefits outweigh the risks.
gpt
The landing gear cause a tremendous amount of aerodynamic drag at the high air speeds attained in commercial aviation. As a result, with gear down an aircraft can't fly as fast and burns significantly more fuel (for a large passenger jet, roughly twice as much fuel for the same distance traveled). Given that a jet might burn more than 100000 liters of fuel in a given flight, that does not represent a negligible cost.