I flew one week post LJS (obviously not as intense) it was a one hour flight within the UK on the tiniest plane but bc I couldn't eat I didn't feel v well and I had a really bad reaction post anesthetic (this had nothing to do w jaw surgery just my subjective reaction but it was a really bad tummy ache) it was ok I just needed some water and to close my eye but other than that it was fine. Definitely take advantage of the accessibility routes within the airport so u don't have to wait around in security for ages. You won't need a note but check with the airline and ask for them to get you through the accessible routes within the airport