I just wanted to share something I've been able to successfully do regarding National rentals.
I work out of BNA and quite often have fires I have to get too around the South and places that are too close to fly.
BNA is ALWAYS out M-W for short term rentals if you are trying to get them under 24 hours and the front desk or the person working the rental areas are never helpful and usually tell me I'm SOL. This has happened 3x times
3x times, I've gotten a rental still.
How?
Working with the agents on the phone and not taking no for an answer - escalating has helped, too.
Two of the times, I had the agent change the length of the rental to be able to trick BNA's inventory to allowing me to go and just tells me, return on the time you want and not the length of the rental and you should be good to go.
On of the other times, I had an agent force the reservation even with the front desk, online and the person working the area to tell me no. I've gotten some mean looks after I directly tell the agent that I will get a car