The budget long-haul airline was ranked cheapest according to its economy airfares displayed on the Rome2rio website in January and February. It beat Air India Express to the top spot, while in third place was a sister brand, Air Asia Indonesia. Denmark’s Primera Air, which now operates in the UK, was fourth; and India’s IndiGo Airlines fifth.

The study analysed over 1.5 million economy class prices from 200 airlines, with the average cost per km across the full list rising from 17.75 US cents in 2016 to 18.8 US cents in 2018. The survey found that while British Airways cost 20 cents per kilometre, Iberia Express and Thomas Cook were only 14 cents.

Among the survey’s top 30 cheapest, 24 were based in Asia or the Middle East. Ryanair, at number seven, provided the best value for travel within Europe.

Kirsteene Phelan, Rome2rio chief operating officer, said British travellers seeking the best value for money “may need to forgo any loyalty they may have to particular airlines and investigate new or charter airlines”.

“Particularly for routes within Europe, if you are happy to spend a little bit of extra time travelling and connect via cities such as Madrid, you should be able to save on airfares,” Phelan said.

“Paying less for a seat may mean travelling without luggage or being left with a middle seat on a long-haul flight. Travellers are increasingly being asked what price they will put on comfort and convenience.”

The survey found significant shifts since its 2016 report, with budget airlines having to pass on higher fuel and operational costs, among them Norwegian, which has dropped down the ranks from 86th cheapest to 102nd.