How far is Hertz car rental return to the terminal at JFk?
At JFK, car rental pickup and dropoff is done at a separate site away from the terminals. People who drop off cars typically will have to drop off their car and then take the AirTrain from the Federal Circle station to the terminal they are departing from. Given security restrictions, I don’t believe that you would be allowed to leave an unattended car in front of the terminal while you checked your luggage, then returned your car. (If you have someone traveling with you, it might be a different story.) You would need to either park the car near the terminal, bring your baggage to the gate, and then return the car, or find a way to get it on the AirTrain to the terminal.