What are an airlines "requirements" if your flight is cancelled for mechanical reasons? I was recently cancelled on US Airways out of Philadelphia, they told me that they could only resechedule me on a "partner" airline, such as United, which had no flights. I asked about Southwest and was told that I was on my own if I wanted to go with them. Consequently I had to wait six hours for US Airways next flight.

I alsways thought all airlines had an agreement with each other?