Could the S.H.I.E.L.D. C-17 actually have a sensible center of gravity?
Might have been better as a canard design.  Yes, you can have two wings bearing weight with the CG in between.  But the fore wing must stall first.  This C17 would have problems unless there was a lot of weight up front, or if the rear wing(s) stalled first.  But note that the extra engines could go on the main wing, or the second wing could be mounted above or below the first, or even in front, making it an Avanti Piaggio from hell.  This design actually might have a chance if the T tail was removed as the transport version of the B-58 Hustler.

But for the movies, this design will certainly do.