Our flight for this year (and last) had changes in time which we found unacceptable. Delta bent over backward to rearrange our flights. In fact, last year we flew a day earlier than we anticipated (hence arriving the afternoon before we planned to) and this year we will be leaving a day later. The flights we were switched to priced out higher than we had paid for our original flights BUT we weren't charged any more for them!
Last year we took an afternoon flight on a Friday and spent one evening at POR before checking into Polynesian. It enabled us to arrive at Polynesian for check-in at 8:00 a.m.--just in time to hit the concierge breakfast and be off to the parks at opening.
This year we will be leaving on Sunday rather than the planned late evening flight on Saturday. This will allow us to spend the entire day Saturday (into the evening hours) and still be rested for our return flight on Sunday a.m. We will be spending the night at the Hyatt Regency the night before we fly. The best part is arriving home in the afternoon on Sunday (while not cutting our park time short on Saturday) rather than arriving home at midnight or after!
It sure doesn't hurt to put on your best schmooze and see what the airline will do for you!