Planes waste the most of their fuel on takeoff, so why not put linear accelerators on the runways of major airports and use efficient and potentially renewable energy to get the planes off the ground? Once the plane is cruising it's very efficient, and we can already relay half the task of accelerating the plane to the ground, so planes will use less fuel or be able to go further with the fuel they have. And you can't say "reliability" because the best part about those is that without the catapult those catapult runways just become runways.