Airport concession recovery fee
This is the single largest hidden fee at any US airport rental — typically 10-12% of the base rate, sometimes higher. It covers the airport's percentage cut from rental brands. You cannot waive it at airport locations. To avoid it entirely, book at an off-site location 1-3 miles from the airport (most brands operate one). Compare the daily savings against shuttle/Uber cost both directions.
Refueling charge
Returning a car with less than a full tank triggers a refueling charge of $9-12/gallon — three times the pump price. Fill up at a station within five miles of the airport but outside the perimeter. Don't accept the 'pre-paid fuel option' unless you're returning the car nearly empty.
Toll transponder fees
Most rental brands charge $4-7/day plus actual tolls if you trigger any all-electronic toll, even one. If your route only crosses one toll, paying cash or buying a one-day visitor pass yourself is cheaper. If your route is full of tolls (Florida, Texas SH 130, NJ Turnpike), the transponder is worth it.
Drop-off fees
Returning the car to a different location than pickup triggers a one-way fee. Within the same metro area, this is usually $0-25. Cross-state returns can run $200-500. Always confirm the drop-off fee at the time of booking — it's frequently larger than the rental itself.
Additional driver fees
Standard surcharge: $13/day per additional driver. Three exemptions are common: spouse (free at most brands), corporate accounts (usually free), and AAA members (waived at Hertz).
Young driver surcharge
Renters aged 21-24 pay $20-30/day. There's no way around it except to have an older driver on the reservation, or to book through services like Costco Travel, which sometimes waive it.
After-hours service fee
Some airports charge $25-50 for picking up or returning outside the rental counter's open hours. Verify counter hours before booking a red-eye.
Cleaning fee
Sand, pet hair, smoke smell, or interior spills can trigger a $50-450 cleaning fee assessed after return. Vacuum sand from beach trips before returning. Don't smoke in the car. If you travel with a pet, pay for an interior cover.