"...The F-18 needs about 20+ mph for launch in order for the control surfaces to BITE the air..."

I would not dispute that at all. But 20 mph is just about 30 feet/sec. which sounds like a mighty toss for a hand launched plane. Last summer one the the guys had an F18 with a MF480, MEGA 16/15/3 on 11 cells. He could launch it by running then throwing.

Two other options are available. You could always mount fixed landing gear. Or you could use a bungee launch.

Bungees, when done properly, will get your plane to 45 mph and 30 feet of altitude in less than a second. But a bungee launch gone bad is not a pretty sight.