If you're going to rent with Avis at the Key West location, please be sure you have back up plans, or multiple reservations with other businesses. Apparently there's a really poorly managed branch where they're crazily overbooked in comparison to inventory. I've heard it's been a consistent issue over the past several weeks, and even before Irma, so please be aware. While 3 flights arrived, all of the Avis folks about 30 of us that had reservations stood around waiting because there were no cars available. They just took last names, not phone numbers or anything else to try to contact you should a vehicle be available. My flight arrived at 11:30 in the morning, cars were unavailable until about 4:30pm that day...without knowing precisely how long to wait, several people cancelled their reservations and took cabs, or booked with other agencies on site.
There was a shipment of cars that arrived at 4:30pm that day and certainly out of vehicles when I inquired about them onsite again around 8:30pm.
I returned on the following day, and it's the same situation. Needless to say I was extremely disappointed...I hope you enjoy your travels to KW and do not experience this issue!