Aha! This sounds like a problem for (*runs into telephone booth, gets changed)
CAPTAIN SWITCHTRIGGER![/b]
Create your group of planes in the mission editor. Give them a hold waypoint somewhere out of the way, out at sea. The next waypoint should be seek and destroy, or destroy a certain object, whateer you want. Now create a trigger, activated when you want the planes to come in a attack. Make the trigger type switch. Synchro the trigger to the hold waypoint. You'll have to do some playtesting to get the hold waypoint in just the right place to get the timing right.
There are various tutorials in the Ed Depot covering switch triggers, which are a vital tool in the mission designer's armoury. Post here again if you get stuck.