The predictable congestion gets a bit tedious and makes the game impossibly difficult quite quickly. It guarantees needing to keep readjusting almost every plane, otherwise a crash happens while trying to select the correct plane to move. It's a great mechanic earlier on and as a tutorial, because collisions happen rarely, but knowing that so many planes spawning or taking off on a calculated crash path when it's already chaotic seems to actually take skill out of the game as it progresses.
Planes that land should turn gray as it's confusing vs. planes taking off (especially consecutive takeoffs).
Volume slider rather than just on/off.
Drawing paths to the landing area should be more forgiving. If there's a short section of weird path at the end, it messes up timing for the planes landing and causes crashes.