I guess it's functional but your wings clip into the ground, there is ground collision and even some object collision but could do with more.
I can't tell if your modelled the sphere of the world or if you modelled ground effect... I'm guessing the former since you didn't model gravity!
Can I suggest when you land that the plane throttles down? (I couldn't find any throttle control and there's no UI for it either way). Also the jet sound stopped after a minute or so and didn't come back - it made no sound at all but maybe the jet sound is the only sound in the game so I don't know what broke.
Also the most important missing feature is a quit button (no mention of one and neither "q" or "Esc" work so I had to use "Alt"+"F4").
But as far as it goes, it seems to be stable and runs which is a plus compared to quite a few games on here! :)
Hope it goes well :)
P.S. Feature request... if the map is randomly generated can you add a directory where players can mod it by adding building files to be added to the map (even if just to have things to find! :D