As someone who does quite a lot of long haul flying (maybe 24 trips in the last 3 years that are usually 20-30 hours each) -- I generally try to sleep as much a

As someone who does quite a lot of long haul flying (maybe 24 trips in the last 3 years that are usually 20-30 hours each) -- I generally try to sleep as much as possible because it passes the time and gives me a good chance to be setup for avoiding jetlag. The ideal situation for these long hauls for me is to leave the evening local time - sleep a fair bit of the flights (maybe half at least) but then you still arrive tired enough in the afternoon-evening of the destination time that you can sleep most of the night. That seems to work the best for timezone reset for me. If you arrive at your destination in the morning to early afternoon - leave the hotel and walk around preferably outdoors in the Sun as much as possible until at least about 5PM preferably 7PM. If you didn't sleep much (or even if you did) and you have a bed nearby there's a good chance you'll end up sleeping until about midnight and then you're double jetlagged :)