Holidaymakers could be left stranded at the airport as a Europe-wide shortage of hire cars hits travellers.
Bigger bills are also facing those who manage to find a car, because a shortage of supply has resulted in the price of hire cars doubling in some places.
Fleets cut due to dire forecasts
Predictions that recession-hit travellers would stay at home meant that hire firms have cut their fleets, and had difficulty obtaining finance to replace old vehicles.
A rush in last-minute bookings has confounded the forecasts and left many destinations without any hire cars.
Spain is the worst-affected area, with those who can get a car having to pay double the usual rate.
With small cars in particular demand, hiring a larger vehicle can often prove to be cheaper.
President of Hertz Europe, Michel Tirade, said: 'There's a seasonal shortage of rental cars every summer, but it seems to be more acute this year because carmakers have cut production due to the uncertain economy.
'There has been a big increase in domestic and US inbound travel, and holidaymakers are deciding to go away at the last minute.'