Hey,
I moved from Israel to the USA with four cats on flight (11 hours to NY and 2 more to chicago) We had them all under the seats, in a dark carier that is pretty dark inside. None of them were drugged, and they were fine. Only one of them was meowing for a while but it wasn't too bad. The baby in the next row was much louder.
Don't worry about the cats, they handle the flight better than people, at least mine did

Efrat