My personal experience,
do not rent a car from Enterprise, if you are going to drop it off INSIDE JFK.
They offer you a drop-off in JFK, but the location is actually NOT inside JFK, it's somewhere on the street.
If you are not familiar with the location, you will never be able to find it while you have a plane to catch up.
And frequency of the shuttle bus is 1 HOUR.
When I called to book the car, they did tell me that I was able to drop-off the car INSIDE JFK. Such a trap!
Long story, but they ended up charged me $486 for a 12 hour rental car from Enterprise.
Hope it helps!
Be careful with the drop-off location in JFK.