This happened to us as well, only with US Air. We booked through Expedia, and when I called them to complain, they said they could do nothing for us. I looked up the flights available on the US AIR website, and called US AIR right away. I was hopping mad, because we had bought our tix last JULY for this APRIL trip, in order to get the late departure times that we wanted. US AIR was very gracious and changed our early departure from MCO back to a later departure (4:30 p). They did want to charge us $100 per person for the change, but relented when I complained that THEY had changed our times in the first place. I wouldn't have complained if they'd changed our time by an hour or two, but I think anything over a 2 hour time change--you definitely have recourse! Call right away, as when I spoke to the US Air rep--she told me that if I hadn't called then, there might not be any later flights still available, as most were SOLD OUT. Even though our flight is in two months now, I'm still checking frequently to make sure there aren't any more significant changes. Good luck and let us know how it goes!!