Tail Numbers and Flight Numbers Don't Match

For those airlines that do report tail numbers, almost all of the flight numbers shown are different than just tracking without a tail number. Here’s an example. I saw an A320 numbered N108UW on July 17th landing at ORD at about 6:42pm. When I look up ORD arrivals, I see US Airways 703 from PHL, an A320, shown at that time. But if I put in N108UW in the tail # tracker, I get a page of tracking for N108UW/AWE829. Looking down that list, it does show that flight from PHL to ORD on July 17 at the same time. So, which is the correct flight number - 703 or 829?

At first I thought maybe there’s a difference due to aircraft swaps but this pattern repeats for almost every plane I have spotted - United and Air Canada as well. C-GSJB has two flight numbers associated with one route on July 17 from YYZ to ORD. I don’t know why that happens.


AWE829 is the flight that N108UW is operating at the moment which is shown when queried by tail number. AWE703 was the PHL-ORD flight and N108UW shoes when you click that flight for that day.

Ok…but here’s another situation. N441UA on July 17th at 6:42pm is shown as landing from DCA. Then, at 8pm it is shown as departed for ATL. But it is also shown as operating LAX-IAD at 10pm PDT. It would be impossible for this plane to do both flights. Then, the next morning it is shown as leaving ORD at 9:14am. How did it get to ORD? Maybe a ferry flight from IAD, since it landed there after a red-eye at 5:30am? I don’t know. Tracking an airliner by tail number doesn’t seem to follow a logical timeline for its flights.