Years ago a doctor prescribed Valium for an upcoming flight to Madrid. He said less after affect than a sleeping med. Later I used 1/2 Ativan (don't rememeber the strength) at home for sleep until a doc re-routed me to Restoril, then another doc claimed that to be bad and gave me Ambien. Now everybody is down on Ambien.
Point is, they all worked fine for me, but I'd go with the Valium/Ativan to take the edge off, which Ambien doesn't do. These days I'm no longer afraid of death and the dull roar of the engines often puts me to sleep before takeoff, so I don't use any meds.