It actually has a mechanism that forces the engine to turn over as it's launched, so if the engine is well-maintained (like it damn well should be) it'll start just as the plane leaves the Zeppelin. So, all the planes that have been launched have had their engines start up, but, due to the near-vertical drop system all the launchers use, Every plane launched has to pull out of a near-vertical dive. That's why it's safest to drop the plane above 3000 feet, just in case something goes wrong.<br/><br/>Thankfully, some planes, like the Devastator or Raven have such a large lifting surface that they can go from 'straight dive' into 'near-horizontal' within moments of launch due to the relatively low airspeed; they just catch the wind like a kite.<br/><br/>The Bloodhawk, which is designed for Stupidly fast speeds (Its airframe is rated for up to 450 Mph, but its 'default' engine can only push it up to 300) has a narrow cross-section so it tends to 'cut' through the wind, and takes longer to pull out of the launch dive.<br/><br/>Major-Major's Avenger, conversely, has a large amount of drag, so he needs to be sure both engines are at full power before he can pull out of a dive; otherwise he runs the risk of a flat-spin stall which is extremely dangerous to slip into, and hard to pull out of without needing a sick bag afterwards.