Originally Posted by
Mudfish
You have it just about right. For a flight with a stop it doesn't matter if there is a plane change. If it is the same flight number then it is one segment regardless of if you stay on the same plane or they put you on a different one.
If you have a connection then it is a different segment.
That doesn't make sense. Every takeoff/landing pair should count as a segment. According to US Airways web site it states:
U.S. Domestic Segment Tax - $3.70 per flight segment, per passenger. A segment is defined as one takeoff and landing.
So I don't think flight numbers should have anything to do with what counts as a flight segment. Of course common sense doesn't often apply with airlines.