Yeah this is not really going to be a problem. Cars spend a lot of time waiting, so rows of 120V outlets will do plenty. Level 2 chargers can keep busy cars topped up. They could have superchargers for fast turnaround, but as a renter I frankly don’t really care. If there’s a supercharger near the airport (and, newsflash, there is) then all I really need is to take the car and return it at half charge or better. Having it be fully charged at pickup is nice, but not necessary.