For us Brits, it will take a good 90 mins to get through customs, immigration, baggage, then shuttle, etc etc....
I put in the time I want to rent and got my pre-paid cost... put in flight details and clicked the button to go next page, I clicked 'buy' before reading that an extra hour had been added on, as it started my rental time at the time the plane lands when entering my flight number!
smart system, and easy extra money for Hertz