The first wave attack against Bombardiers can easily take a few hours, usually more. You must take the town in 2 seperate wave attacks. There currently isnt an effective way to just kill them all, just an efficient way, as you can only have a certain amount of Gyros on the battle field at once. Bombardiers are devastating against your artillery units. If there are no more flight units, the Gyrocopters do nothing else. Your Gyrocopters automatically attack the Bombardiers until none are left, then move on to any possible enemy Gyrocopters. If the defender has Bombardiers, you must have Gyrocopters, Or you will be slaughtered. The only unit that can destroy the Bombardiers are the Gyrocopter. The Bombardier attacks your Artillery untis first until there are none left, then moves on to attack remaining troops with any munitions they might have left. The 2 Aerial or Flight Units in Ikariam are the Bomber, or Bombardier, and the Gyrocopter.