Question

The question I have, has to do with relativity (or so I think).

Imagine a fighter jet with two pilots travelling at twice the speed of sound.

I would imagine that if the pilot R (rear seat) throws a tennis ball at Pilot F(front seat), it will hit pilot F as the ball was already travelling at mach 2 and it was further boosted by pilot R. (please correct me if I am wrong).

Will it be the same if pilot R shouts at pilot F.(does sound waves act just like the tennis ball relative to the speed of the jet aircraft?)