Those extras can easily cost more than the flight itself and in one instance identified by comparison site Kayak, a mistake requiring a name change cost 26 times the face value of the ticket.

Budget airline Ryanair lists the cheapest flight to Europe at £5.99 but get the spelling wrong on a booking and it will cost £160 each way to amend (£115 online).

Easyjet offers flights from £24.65 but if holidaymakers need to change the name on a ticket, the cost during peak season costs £52 if the flight is in less than 60 days’ time. However, Easyjet does allow passengers to amend small mistakes to names for free.

With Flybe, there’s a flat £50 charge for any changes while Jet2 charges £35 each way. However, Jet2 allows spelling errors of up to three characters to be changed for free.

But if the cost of the Jet2 flight has increased since it was booked, and a required change isn’t made via the call-centre, this will be added to the overall cost of the name change. As such, if a passenger bagged a bargain flight, but the cost of a last-minute ticket on that flight skyrocketed, they could be hit with huge extra fees.

Baby seat prices

In another case, Kayak’s research revealed that parents may even be paying more to seat an infant on their lap than the price of their own ticket.

Ryanair charges a flat fee of £25 – more than four times as much as some of its adult ticket prices. EasyJet charges £22 – about the same as many of the cheapest flights listed on its website – while Jet2 charges £20. Flybe is the cheapest, charging 12% of the adult fare.

When it comes to luggage, the cost of putting your items in the hold can skyrocket. Ryanair charges up to £40 for a bag in the hold if done at the airport, while it’s £25 online. This is over six times the cost of its cheapest ticket. And for those travelling with sports equipment, the cost could rise even further – to £65.

EasyJet charges up to £47 to put a bag in the hold, for Flybe, it’s £25, while Jet2 passengers will pay up to £35.

Allocated seating

Many airlines now also charge holidaymakers if they want to sit together or if they want to sit in a particular area of the plane.

As an example, for those wanting extra legroom seats on the plane, the cost on EasyJet can be £26.99. The cost is £15 with Ryanair and up to £16 with Flybe. EasyJet also charges a ‘group booking fee’ – £10 for each member if they wish to sit together.

Neil Cartwright, travel expert at Kayak, said, “Low cost carriers offer great value for money when it comes to ticket prices and help many Brits get away for an almost unbelievably cheap fare. But it’s on the extras and mistakes where they really make their money.

“A name change can end up costing £320 for a return flight, so it’s worth being extra thorough with these details in order to bag the cheapest fares. In these situations, my advice is to check if it is cheaper to simply book the entire flight again.

“Travellers need to be very careful not to make any mistakes when booking, and to consider the full cost of their flight rather than just the ticket price as you may find that a flight that costs more, but charges less for baggage, or other extras, might be even better value overall.”