Anyone taking friends or relatives to the airport this summer - or picking them up - is likely to be shocked by the cost of parking, says the RAC.
It claims more than half of the UK's airports have increased their charges since this time last year.
Amongst the worst offenders are Luton and Stansted, both of which have raised some of their charges by more than 10%, the RAC says.
However the two airports near London deny that their charges are excessive.
Parking at Luton can cost as much as £8 for up to 30 minutes, or £17 if you go over an hour. However the airport said cheaper options were available.
But it is the introduction of charges for dropping passengers off that is particularly controversial. Fourteen UK airports now charge a fee for drop-off.
£25 for 15 minutes
The drop-off/ pick-up zone at Luton costs £3 for 10 minutes, but charges rise by £1 for each further minute.
Luton airport said there were other car parks which were free to use. However these are a 10- to 15-minute walk away, or a bus ride of least five minutes.
It said 98% of motorists using the drop-off spend less than 10 minutes there, so pay £3.
Dropping a passenger off at Stansted costs £3.50 for 10 minutes, a fee which rises to £25 if you don't leave within 15 minutes.
Stansted said the charge was to discourage pollution, and to encourage people to park in longer-term car parking areas.
It also said the charges help to keep airfares down.
"Revenue generated from car parking and retail at the airport is used to develop new passenger services and facilities, and keep charges low for airlines, resulting in cheaper air fares for our passengers," a spokesperson said.
At Heathrow and Gatwick, the UK's busiest airports, there is no charge for dropping someone off, providing you are quick.
Similarly most European airports - including Schiphol and Geneva - have free "kiss and fly" zones.
"With thousands of motorists driving to airports to pick up and drop off friends and family members, many will unfortunately find themselves shocked by some of the extortionate parking tariffs operated by some airports," said the RAC's Rod Dennis.
The organisation is advising motorists to check parking fees before they leave for the airport, and to keep "goodbyes" to a minimum.