Thanks, FlyVMO! I guessed the cosine bit and found the velocity of the earth is 903 knots, but the effect of altitude is still a mystery.
Not true that the SR-71 could make the sun rise in the west and set in the east--the Concorde could do it also. In fact, any plane flying greater than 903 knots (x the cosine of it latitude) for ground speed long enough could do it. We were SVO-EWR and at 61 degrees north with a 440 or so ground speed, the sun sat just below the apparent horizon for about 7 hours. FL 470.
GF