Very nice. I would like to see it with something less "slick" than a Glassair. Gear hanging down, etc. Like one of the other designs, I can imagine a flash version that cycles through a few different aircraft, and model specific tee-shirts. I'd say you're tied for first right now.
#38 Aircraft seems out of place somehow, and the arc a little bit too much like a smile. I have no idea how to fix it. Maybe just let it sink in a while and see what ahppens. Good stuff.
It occurs to me that when printed on an aircraft, "EXPERIMENTAL" is usually all caps. Make the "X" a capitol and we'll get away from the FedEx brand easily. What do you think of that?
How about the fonting from #32 with the swoosh and aircraft from #57? Feedback around here is that all of the big block letter examples (not just yours) are just too close to FedEx.
Here is a font style that I think looks great. It's fast, it's slick, and I think it ties in well with the aviation theme you're going for - and we get away from the FedEx similarity. Let me know what you think!
OK - no rush on this. Nitpicky stuff. Can you add just a couple of details to the airplane silhouette? Maybe define the canopy and add some shading to the fuse to set the back wing off. Maybe a little red/black stripe down the side. Keep it very simple.
The outside edge of the swoosh seems a little big segmented in the tiny version I have to look at. Maybe it's fine.
Can you also adjust the fat end of the swoosh to match the angles on the tail of the airplane? Consider a gradient in the swoosh as well. The stark white seems a bit plain now that you have such excellent reflections and shading in the fonting. Nothing crazy.