Is it possible to exchange bitcoin for american express travelers cheque?
Well, i'm pretty sure not directly. I've checked for you on localbitcoins and it seems like nobody is buying bitcoin with travelers checks, and no centralized exchange will do this for you either pretty much because it's not a very safe way of depositing money(could be reported stolen etc.).
What you can always do is though:
a) exchange bitcoin to your fiat currency
b) go to your bank branch
c) buy travelers checks from them.
IT's a hassle though and will involve fees. Just use cash, man. Why do you even need checks? I mean nobody accepts it anymore lol