Krautscape 

Krautscape is an action-packed racing game with bird-like flying cars and procedurally built racetracks. The leading player builds the racetrack while the chasing players can take shortcuts by flying off the track to overcome obstacles. The game features three multiplayer game modes that are designed to support nonlinear gameplay and intelligent movement instead of forcing you to drive perfectly. Three singleplayer game modes introduce you to the basic mechanics of driving, flying and track building.