-1, if we include the initial start up from take-off. We're assuming that everything is under ideal conditions here, as we are where every single aspect of maintenence, human-error, supply, etc.
For a game, I think thats as it should be. The entire purpose of playing the game isn't really to see how many aircraft you can vulch on the runway because their engines didn't start up. Or how many Tiger tanks you can 'kill', because they ran out of fuel, and fighter-bombers hit their ammo trucks. I mean in my mind, the entire point of the game is to see how good you are, and if you can beat the other guys in a fight. Get down to the core of that, and the point of the game is to be challenged.
However, if its the mid-flight engine cutters, then hell yes. Learn to work the throttle, or you'll end up as someones free scooby-snack.