DFRC F-16 Fleet and Support Crew 1997. Four different versions of the F-16: On the left and right sides are two F-16XLs. On the left is the F-16XL #2 (NASA 848), on the right is the single-seat F-16XL #1 (NASA 849), between them at center left is an F-16A (NASA 816). Next to it at center right is the U.S. Air Force Advance Fighter Technology Integration (AFTI) F-16. September 29, 1997.