I'm a big fan of Sonata^^

Half life is only 1 hour, it gets you over the hump of falling asleep initially, but doesn't zonk you out if you need to wake up in an emergency or breakfast service has started and you are hungry.

It's also flexible, in that you can take a second dose if you wake up and still have time for another few hours of sleep. So the same medication works for US-EU redeyes which are too short for safe use of Ambien, as well as US-Asia flights which may allow for more sleep than a single dose of Sonata would provide.