They may be the 21st-century equivalent of steerage class, but as you endure the stress, discomfort and sheer cattle-truck misery of travelling with the so-called low-cost carriers, you can at least console yourself with the knowledge that you’ve saved a bundle by not booking with a full-service airline. Right? Wrong. An investigation by Warwickshire Trading Standards states: “When you factor in the ‘extras’, some flights can end up being more expensive than those offered by more traditional carriers.”

Mark Ryder, head of Warwickshire Trading Standards, explains: “A lot of these no-frills offers look cheap, but when you add in booking supplements for paying by credit card, check-in fees for luggage, charges for wanting to sit together and in-flight meals, costs can really add up.”

By how much? Well, paying with plastic will set you back anything from £1.72 (with First Choice) to £4.95 (with EasyJet), or 2% of the total cost of your ticket - minimum £4.95 - with MyTravel and Thomsonfly.

British Airways also charges a £3 credit-card “administration fee” - marketing speak for rip-off – but at least it doesn’t charge you for food. Fly with Thomas Cook and you’ll pay £6.50 each way for meals - that’s £52 for a family of four. MyTravel charges up to £8.50 per sector for what is, in effect, a microwave ready meal and a bowl of blancmange.

Then there’s baggage. Ryanair wants a fiver per bag – and if you forget to check in online, it’s a tenner at the airport. It also charges £5.50 for every 1kg you go over the 15kg limit, so, to match BA’s luggage allowance of 23kg, add £44 to the price of your Ryanair flight. And that £5 check-in fee.

Want to sit with your family? It used to be a matter of asking politely, but now it’s a tradable commodity - £5 each per sector with BMI Baby or Thomsonfly. EasyJet will give you a head start on the rest of the herd with Speedy Boarding, also £5 each way, but again MyTravel takes the biscuit, charging £12-£24 per person.

For the time being at least, BA seems above such things. “We try to seat families together on our flights,” sniffs the airline, “and we would never charge for that privilege.”

So, with free meals, checked luggage and allocated seating, can traditional full-service carriers really compete on price?

We put the old heavyweights in the ring with the no-frills contenders to fight for five holidays - a week in each of Spain, Cyprus and Florida, and weekends in Amsterdam and Dublin. The rules were that we would choose the cheapest deal on the day in question, giving maximum and minimum prices for each no-frills carrier.

The maximum price includes excess baggage fees, to equalise luggage allowances up to the full-service carriers’ 23kg, and supplements for assigned seats, meals and on-board drinks.

The minimum price excludes meals, drinks, maximum free luggage allowance and allocated seating.

The results were astonishing, showing that, with all things equal, flights on full-service carriers were up to 35% cheaper than with their no-frills rivals.

And, apart from Thomsonfly’s pummelling of Virgin on the Orlando route - its school-holiday ticket was more than £400 cheaper than the Branson bruiser, which means a £1,600 saving for a family of four - price disparity without the frills was less than expected.

The average minimum cost of an EasyJet flight to Malaga came out at £115.93 over the dates surveyed. BA’s average for the same period was £126.23 - a difference of £10.30, or 60p more than the price of an Easy cheesy baguette, a G&T and a glass of on-board wine.

The Dutch carrier KLM KO’d BMI Baby’s so-called Tiny fares to Amsterdam, and BA beat MyTravel on points to Paphos.

Fancy a break in Dublin? there’s just £8 in it between Ryanair and BA next weekend – go a couple of kilos over at the weigh-in and you’d be better off with BA.

Even if you can resist forking out for the extras, price differences between no-frills and full-service carriers are so slight, you might wonder if the savings are worth the sacrifice.

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