Originally Posted by
jsloan
ContinentalFan is correct — you’ll get the great circle distance between the origin and destination airports. That can be less than your longest segment: at one point, UA’s last AUS-SFO flight of the day continued to LAS — so if you flew AUS-SFO-LAS, you got several hundred fewer lifetime miles than if you’d just flown AUS-SFO by itself.
Another good example is UA2650 LAS-SEA. You’ll actually fly LAS-LAX-SFO-SEA all on the same flight number, but on three different aircraft with lifetime miles awarded as if you’d flown nonstop from Las Vegas to Seattle.