Flying abroad for a holiday is already a fairly expensive process and ideally, you don't want to be saddled with any additional costs that you might not have been aware of.
A number of factors such as late check-ins and your baggage exceeding the maximum weight could impact the overall cost.
In fact, if you managed to tick off all the hidden costs for one particular airline it would total up to an additional £220.
As reported by The Mirror, the financial news site TradingPedia compared these fees for seven airlines that fly from the UK to Spain, Portugal and other European hotspots.
These charges include more obscure ones like a rescue fee which is the charge for transferring to a new flight after missing your original one.
This is only if you arrive at the airport no later than a certain amount of time after it was due to depart.
What are the airlines with the most expensive 'hidden fees'?
The airlines analysed were Ryanair, Wizz Air, easyJet, British Airways, Vueling, Norweigan Air and Jet2.
The factors analysed were fees for checked baggage, carry-on baggage, seat selection, online booking, airport check-in and the rescue fee.
1. Ryanair (£31 for checked baggage, £18 for carry-on baggage, £15.50 for seat selection, £0 for online booking, £55 for airport check-in and £100 for rescue fee) - £220 total
2. Vueling (£41.50, £38.30, £16.10, £0, £0, £115.30) - £211
3. Wizz Air (£57.40, £0, £29.30, £9.80, £24.30, £73) - £194
4. easyJet (£31.50, £17.50, £24, £0, £0, £110) - £183
5. British Airways (£50, £0, £20, £0, £0, £0) - £70
6. Norweigan Air (£27.90, £12, £27.90, £0, £0, £0) - £68
7. Jet2 (£31, £0, £20, £0, £15, £0) - £66
Michael Fisher from TradingPedia said: "The report includes information about fees charged by seven airlines, of British Airways, easyJet, Jet2, Norwegian, Ryanair, Vueling, and Wizz Air.
"To be fair, fees are not exactly hidden on the websites of the airlines – they are fully disclosed on each screen while you are making an online booking.
"However, they are not added to the final cost of the fare in advertisements and special offers, and do not become clear until the actual process of booking the flight is completed."
Additionally, TradingPedia warned that in some cases, passengers had no choice but to purchase "optional" services such as WizzAir's group booking administration fee of £4.50.
Likewise, anyone flying with an infant under the age of two doesn't need to buy a ticket - but Wizz Air charges £28.50, while easyJet and Ryanair add £25 and Jet2 charges £20 in fees.
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