The bombs that a plane drops are the 'laser guided bomb'. I think you can get the plane to drop its bombs with the 'fire' command. Check the COMREF
here for info on the various commands (though make sure you select OFP as the game).
You could also try one of the artillery/airstrike scripts available in the
Editors' Depot. They're a very effective way of simulating an accurate airstrike.
Hope this helps (been a long time since I touched the OFP editor)
Gruntage