Only airline that ever lost my luggage. And it's not that it didn't make my flight. I got on in the originating city, and they took it off in the city we stopped briefly at. Why? Who knows.
For the first 30 hrs of my vacation, they did not know where it was - literally told us they couldn't tell us when it would be delivered because they didn't know where it was.
Within a couple of hours of hearing that for the third or fourth time, my hotel's front desk called to say they had delivered it.
So the best I can say is that it was probably a fluke, but if it happens to you, the likelihood of the people taking your phone calls (on the few occasions you can get through the automated phone tree to an actual person) knowing what the status of your bag is, is slender. But you might end up with the bag anyway.