To win: Hit the target.

How to play:
Obviously, this could be just a simple race. Get a plane, take off, winner is the first person to crash into the target. The big, important rule that I am suggesting is that the throttle must be kept at 100% from takeoff. This, I find, is what makes the game fun. I also recommend certain targets for the flight path, such as requiring planes to exceed 15,000mi, and 1000mph.
Creative minds will notice that the full-throttle requirement can be cheated by using very little fuel. Of course it can - that's a risky strategy.
Once you've mastered this, you can add limits to size, weight, and complexity of the machines, but the real test is to fit the front of your dart with a Boom 50 or three, and making the target something destructible.
For first-time players: use the "Jump Zone" location in Skye Park City and attempt to hit the USS Beast, with a flight that must exceed 15k feet in altitude and 1000mph, in a plane that weighs between 5k and 10k lbs.
Good luck!