An aircraft appears as an icon on the title screen but this mode of transport is not found on any of the game maps. However, it is possible to make it appear using a hack. Board a helicopter and alter the value of address A7B to 1B to change the vehicle model to the aircraft. The helicopter control method is still retained using this method.  There is a secret vehicle called the "Amphiunisuperduperbigmobile". In order to locate it, start the game in Hunter mode, go to location 200/249 and swim north to 200/250. There is a hidden entrance which can be difficult to locate. Inside there is a room with seats, flags and the vehicle, which can be boarded and driven outside.