I’ve noticed the only “friendly” tails that I can track with them are their 737-800’s and their 737-700’s that carry four digits in the registration numbers. I you try to track their three digit planes you either get their registration with an associated flight number or you can have a flight number without an associated registration. Any idea why Southwest takes this position given their high interest in tracking their specials?
With any tracking system you can only track their 737-800s and ex AirTran 737s.
If you look there are other forums on this topic.