Do I have to bring someone along, or can I drive after the thigh lift?

No driving. You won't be driving for a while after a thigh lift. The incision is tight, and one of the risks is having the incision separate (dehiscence).
Driving after TL. Definitively not recommended for multiple reasons. It is likely that you will need some sedation or anesthesia and should not drive just because of that. On top of this you run the risk of increasing the chances of complications including wound separaion, hemoatoma, bleeding, among others.
Driving post op. Unless your procedure is done under a straight local anesthetic with no sedation, it is highly unlikely that you would be allowed to drive home.