I believe that a C5 transport jet can fly at about Mach 0.7 .
Today’s invention aims to increase the top speed of all such transport planes with a rear pallet loading system (and a strong enough air frame).
It might get in the way of airdrops, but imagine a pallet consisting of a liquid fuel jet engine. The rear door could be opened and the jet smoothly ignited to provide a burst of thrust to evade eg SAM missiles or to effect a sharper take off whenever necessary.
The jet pallet itself could be parachuted out and recovered if stowage forward needed to be dropped.
