Calling in an Airstrike (help please...!)

[Xalamandros]

Could somebody please help me out? I'm trying to get through "The Last Stand" and am getting obliterated every time! The guy who made the video walkthrough (on youtube) calls in airplanes as reinforcements. But my screen shows no airplanes or tanks on the right panel. They don't appear at all (not even grayed-out). Is there something wrong with my game? Or do I need to do something special to make the airplane icon appear on the right? I would be so grateful for some help! Thank you!

Stephen