As long as the prop is turning over, engine will restart. Just like starting a car with a manual shift rolling down a hill. Drop it into gear, key on, pop the clutch and vrrrmooom away you go.
WWI planes, fixed wooden prop, at 50 mph and above creates a lot of force on the prop, enough to keep it windmilling over. Turn the spark back on and VrrrOOOOOOOoooooom away you go again.