Originally Posted by
ISTFlyer
CLT-RDU-CLT also has the same flight number on some rotations.
It's not just short-hauls.
AA1585 flies PHL-LAS-PHL. AA 1551 flies MIA-LAS-MIA. AA315 flies MIA-PHL-MIA.
The practical effect is zero. If you were on a flight with a single number that went, say, CLT-GSP-RDU, you would probably not get the 500-mile minimum for each segment. Years ago, before the advent of loyalty programs, I would frequently fly from DCA to BUF with a stop in SYR or ROC, and not even get off the plane. That was on Allegheny Airlines, which tells you how long ago it was.