The current flash sale on Hertz gets me a rental car for 4 days at a little less than $100, which ends tomorrow. I'm still have to book my tickets, but the dates are confirmed 100%.

Since the flash sale involves me to prepay for the rental car, would it be possible to select an reasonably early time (looking at the current arrival times on the airline website), and arrive later than the scheduled arrival time?

Also, is there a penalty for dropping the car off a few hours early?