I dislike flying, but I have a few flights coming up.
I find that engaging in "real thinking" about problems while on a plane is generally beyond me. (I'm jealous of all of you that somehow manage this.) Similarly (or Even) writing code takes more focus than I can manage on a plane. But I do try to make my plane time useful.
Luckily, it's the end of the semester, so I think I'll be bringing the last homeworks and final exams to grade on board this time around.
Reviewing (conference) papers is something I manage on plane flights. I'm sure that says something about the level of my reviews. On the plane my goal isn't to read the paper in same depth that I'd read a paper I'm trying to understand for my research; it's to assign a score (sort) and write down useful comments. (Which, I guess, is my goal for conference reviews off the plane as well. And why I wouldn't do journal reviews on planes.) If you get a review you don't like, I suppose now you can always assume you can assign the blame to the fact that I was on a long plane flight. But I don't think I'll have any reviews this month.
Reviewing proposals is even better than reviewing conference papers on a plane. I often get foreign governments sending me proposals to review for them, and they often pay some nominal amount. If I know I have a flight coming up, I sometimes say yes. It makes me feel like I'm doing something useful on the flight, and even getting paid for it.
When all that fails, I try to read a mindless book. (It's always good to have one on hand for those interminable periods where your electronic devices must be turned off.) I slipped up and started reading V is for Vengeance at home. (I think I've read all the Kinsey Millhone books from A, but I started at around H, and can't recall if I found all the earlier ones. I wonder what she'll do after Z?) I've been saving Mockingjay for a plane flight though. (I try to read what my kids read. So I'm also quite familiar with Percy Jackson.) I've read most of Robert Parker's books in the air.
Finally, sometimes, I fall asleep. I've gotten reasonably good at sleeping on flights. Then I don't get the work I thought I'd get done on the plane done. But it definitely feels like a good use for the time.