the best ATC game on the App Store
Some suggestions are
If two planes come face to face you just lose it would be better if you have more control of the situation
There should be a go around and cancel takeoff buttons
A continue were you left off instead of have to start off with the planes are all at the gate in other words save progress were we last so if there are planes by the runway these planes stay by the runway
Large planes should use more runway than small planes
An airport with a lot of runways
the traffic of the planes gets heavy and slow and heavy and slow and so on