Beware of hidden fees when booking with these airlines...

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You might think you've found a great fare after finally choosing your flight, only to find that additional costs keep being added as you proceed with the booking. These so-called hidden fees can vary depending on the airline you choose.

You might think you've found a great fare after finally choosing your flight, only to find that additional costs keep being added as you proceed with the booking. These so-called hidden fees can vary depending on the airline you choose.

Banks aren't the only ones charging customers all kinds of hidden fees. In the airline industry too, travelers are often confused by the addition of extra fees once they've finally chosen their destination, flight time, fare category and other options such as oversized luggage. As vacationers start to think about summer plans, a British financial news platform called TradingPedia has investigated the true cost of these fees that aren't always made clear at the beginning of the booking process. The comparison is based on flights from London to European destinations such as Nice, Madrid, Amsterdam, Rome and Lisbon.

It's certainly no secret that some carriers, especially the low-cost airlines, charge an additional cost for luggage after consumers select a flight. Similarly, seat selection is sometimes not free. But other costs can be less obvious. For example, the research identified online booking fees, charged at £9.80 (approx. €11) per passenger by Wizz Air. The Hungary-based low-cost airline is the only one in the survey to apply this kind of charge. There are also check-in fees, which can be as high as £55 (about €62) with Ryanair, £24.30 (about €27) with Wizz Air or £15 (about €17) with Jet2. And then there's the rescue fee charged by airlines when a passenger misses their plane by a small amount and is given a seat on the next flight. It's best to make sure you're on time to board the plane, because this extra cost can amount to as much as £115.30 (about €130) with Vueling, or £110 (about €125) with EasyJet or £100 (about €113) with Ryanair.

In the end, the Irish low-cost airline takes the prize for the most expensive hidden costs, at £220 (about €250). In fact, low-cost carriers are unsurprisingly the leaders in this ranking, such as Vueling (£211, or about €240), Wizz Air (£194, or about €220), Easyjet (£183, or about €207), Norwegian (£68, or about €77) and Jet2 (£66, or about €75). Meanwhile, hidden costs with the UK flag carrier British Airways amount to £70, or about €80, according to the research.

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