i'm going on the trip my mo doggy too, he is very noisy and a barker:-) if he doesn't bark, he will start crying, like a baby. i don't think that he would sleep through the flight, so my trainer recommended rescue remedy. Its natural and safe stuff.
iHerb.com - Product Details - Bach Original Flower Essences, Rescue Remedy Spray, 20 ml (0.7 fl oz)
you have to spray it 45 minutes prior and your doggy will sleep through the flight.
I'm very nervous myself:-( Good luck to you too:-)