Knights of the Sky

Knights of the Sky is a World War I flight combat sim where you pilot one of the 20 different crafts available (each handles differently!) as you engage in simple missions or join a full campaign where you will progress through World War I where you will go on variety of missions, patrols, and even encounter enemy aces. You can engage balloons and blimps, enemy fighters and bombers, even strafe group targets such as supply trains.

Its main feature is capability of modem link so you can challenge fellow modem owners to dogfights, something that none of its contemporaries had.