I'm not exactly sure where to this question

I'm sorry if this question is being put in the wrong place but I kind of need an answer to it. Okay well my husband and I are moving to Virginia, and we have two cats. It's a 11 hour drive, and I don't want my fur babies to be meowing their head off throughout the whole trip. So i was wondering if a vet has like a pill or something to help make them go to sleep for a few hours for the trip. Does anyone know if they do and how much it may be?