Quoting tonys_mama(army wife):" We drove 16 hours with a 2 year old and a 5 month old. It really wasn't all that bad. They slept a lot. We just made lots of stops to feed, change and let them stretch. I would do it again."
This. We did an 18 hour drive when Wesley was about 5 months old. We had to stop every 2 hours, so the drive will probably take you at least 2 days to do. We did it in 2, very long days.
I've also flown multiple times with him. He does great on airplanes; he loves them actually. I've done international flights, and flown alone with him numerous times as well (he's a well-traveled baby lol).
Flying is way easier, but the driving is a lot cheaper and not as horrible as people are making it out to be. DS falls right to sleep when we get in the car, though. If your LO hates the car, I would definitely make it a flight.