The Helicopter is the only aerial vehicle in Sub Rosa. Faster than all cars, it can easily disable any vehicle it comes across, granted that it has at least one passenger serving as an extra shooter.
Helicopters can be purchased from any of the two car shops in-game, but they spawn at random times.
Due to the expensive price tag, helicopter keys are a rare commodity, giving whoever sells it $750,000, as long as the helicopter is not disabled/broken.