Finally getting around to posting a project I worked on a year ago at MIT Lincoln Laboratory. We 3D printed (FDM on a Fortus 400mc) a UAV with telescoping wings. Structure was primarily FDM except for a carbon fiber backbone that all the parts were attached to. Designed to be highly modular, the aircraft was essentially 3 reconfigurable pieces: the fuselage pod on the front with the avionics and batteries, the wings, and the empennage. To adjust the CG for different payloads you could move all the parts around until you balanced and had the stability margin you needed.
We printed the wings without support material and with an internal structure that made them pretty strong. We also decided to incorporate carbon fiber spars into the wings which essentially doubled our strength to weight and it took less than a minute to install. Combining COTS materials with FDM really helped alleviate some of the strength concerns we had.
I've attached a talk that my coworker and I did at the RAPID additive manufacturing conference this year which has some of our lessons learned and more information about our aircraft. Hope there is something helpful in there for anyone interested in doing FDM UAV design! RAPID Presentation