Weird flight physics, when you run out of "momentum", you drop like a stone. Plus, its very difficult to actually control the flight with the spacebar mashing. Cool weird music and gfx, tho.
Ok - the license tests and races didn't end because I glitched the game by entering and then exiting multiplayer mode. If you do that, speedometer disappears and the license tests do not end. However, without the game glitched, you only earn $1k in the only race available, and everything else in the game costs tens of thousands of dollars. It's gonna take hours of grinding that first race to unlock anything.
More bugs - Most of the license tests cannot be passed, there is no checkpoint to finish. The race mode doesn't end, doesn't count laps. Car physics are odd, its impossible to understeer as if it auto-brakes, and turning at low speed acts as if you're on ice. The speedometer tends to disappear. Very strange that a game seemingly this deep would be released in this state.