Zolpidem (household name is Ambien in the US) is "good stuff", better than temazepam, but should be used sparingly and wisely. Probably could help aircrew on layovers if used sensibly, but likelyhood of misuse is there (ala alcohol), and if you have an accident and it's found you have used it, you know who will get the blame. Simple things like keeping well hydrated, avoiding alcohol, and sensible eating will also help jetlag a lot and not risk your licence or passengers' lives. Didn't the USAF just use amphetamines?