Hecatee
Donor
Since we are talking mainly about terrorist or rebel groups fighting an assymetrical conflict, what about more wide use of unmanned systems by these groups, such as RC planes or balloon-bombs like the Japanese used in WW2? Any truly improvised airforce is pretty much disposable anyway - the planes are likely to be used once or twice at most. before they are eventually destroyed Actually, in many ways it could be argued that Al Queda made very effective use of an improvised airforce against the most powerful military force on the planet.
Well we know that Liabn's Hezbollah used drones during last summer's war against Israel, both Iran and home built models. The thing is that those systems will not be able to operate well in offensive operations due to a probable lack of terminal command...