There’s also the fact that you can often rent the same car from the same company significantly cheaper by going to the next closest car center 10 miles down the

There’s also the fact that you can often rent the same car from the same company significantly cheaper by going to the next closest car center 10 miles down the road from the airport. When I visited San Diego circa 2015 it was actually cheaper to pay for a ride share from the airport to an Avis in town instead of renting from the Avis at the airport (this may not be true anymore as rideshare companies are no longer subsidizing at the level that they were around 2015). Airports often add on additional taxes and fees to car rentals on top of the supply and demand convenience that the rental company charges you.