I've always been nervous about taking drugs on a flight... maybe it's the helicopter egress survival training or the stories about frisky passengers seated next to you or the time I was in a plane that skidded off the tarmac; all occasions where one does not want to be in a groggy state of mind.
What about an intense work out before heading to the airport. A vigorous vinyasa yoga followed by the appropriate cool down / meditation always puts me in a calm frame of mind.