I have booked directly with AA and through Expedia. Our April 2017 SXM trip was booked through Expedia. I sent an email to AA about the Irma situation and they did offer to re book another destination and waive the change fees. I called Expedia about the concern and they were extremely helpful and straight up canceled our flights and returned our money, with no fight at all. I did eventually re book that vacation elsewhere, directly with AA when i figured out where i was going. AA changed those flights on me, i called them and they asked me what flights would i like, and changed them with no hassle. So i really have had good luck both ways, and Expedia felt like and extra layer of protection in that particular case.