Well, that pretty much rules out ambien as a useful sleep aid if you have to wait 24 hours, but if there are legal sleep aids that are effective and only require 12 hours, I just might look into them.
All too often, I fly an 18 hour duty day and then get released for 24 hours. Naturally, by the time I get to the hotel, I'm tired so I go to bed for the normal 8 hours. When I wake up, I have 16 hours before my subsequent 18-hour duty day even starts. As the body clock would have it, 16 hours goes by before I'm even tired again, and then it's time to go to work. 24 hour layover really suck; they should be outlawed. I'd rather have just 12 off.