Oh, acorn. You poor thing! I hope that gets better soon.
As far as plane survival tips, I must admit it could have been much worse. It was all fine at any particular moment, it was only hard because there was so much of it, if you see what I mean. I was more worried than I needed to be. He didn't cry, he had some naps at least, he was mostly happy and smiley. So don't worry so much! I brought some new small toys and books, a few beloved old toys, lots of rusks, biscuits, rice cakes, etc. And changes of clothes for both of us, as I was then covered in rusk and biscuit residue. I guess my only real tip is to be as minimal as possible on luggage. I was entitled to bring more, but getting me, ds, and just the one carry on rucksack sorted to get on and off the plane was quite enough. We were those people you don't want to be behind at security, too. Oh well. We also had one checked in rolling bag and an umbrella stroller, which is a lifesaver in airports. Oh, my other tip is eat in the airport, as it is hard to do on the plane if lo is a lap child. You can have a neighbour hold your lo while you pee, or I would change his nappy then fold up the little table and hold him while I had a quick pee, then stand up, unfold the table again, put him back on the table while I washed my hands. This was a bit of an advanced manoeuvre!