"Don French" wrote in message

Regardless, it seems to me that the rocket's speed has to be
subtracted from the jet's speed to arrive at the actual jet speed when
you talk about the world's record for speed of a jet plane.

Hmm. Would you say the same for Yeager and the X-1, it having been dropped
from the belly of another aircraft, or is your particular question related
just to the rocket?

Would this same sort of criteria apply to the X-prize given that Space Ship
One was given a lift to an intermediate altitide?

Interesting.
-c