Alliances between airlines that allow them to compete globally could be starting to fall apart, potentially triggering a fresh round of consolidation in the industry.

The prediction comes in a new report on the state of the air transport market by aviation analysts OAG.

It argues that the current row between long-established and dominant US carriers and fast-growing Gulf-based airlines about unfair state aid is a sideshow to the coming challenges.

John Grant, executive vice-president at OAG, said: “There are currently more airlines than can realistically exist and alliances are no longer the only means of international competition.

“Increasingly joint ventures, equity stakes and less formal partnerships are being used, all of which challenge the existing structures and operations.”

Examples of this are Qatar Airways building up a 10pc stake worth about ￡1.2bn in British Airways-parent International Airlines Group in January. Although both are members of the Oneworld alliance, Mr Grant said this is a sign of how traditional relationships between airlines are changing.

“Qatar has been watching BA’s progress very carefully and seen how it has been successful operationally and financially. It sees BA as best in class and wants to be associated with it from a business and investment point of view.”

Perhaps more significant is Korean Air, a member of the SkyTeam alliance, which has announced a code-sharing deal with American Airlines, a key member of the Oneworld.

The three major alliances are Oneworld, Star Alliance and Sky Team

“This highlights how airlines will make decisions outside their alliances which are in their best interests as being flexible outweighs their membership,” said Mr Grant.

He believes alliances will survive in the medium term, though there is “a lot of activity around the edge”.

“The alliances that exist are strong but fractures are possible,” said Mr Grant. “Twenty years ago alliances were a way around regulatory control but that control is easing.

“It would take a brave step for an airline to walk away from an alliance and would take years to unwind the operational arrangements but someone could decide to do it at some point.”

Current cut-throat competition in the industry and thin margins mean that passengers are unlikely to benefit in the form of cheaper flights from OAG’s predicted shake-up.

UK and Ireland-based carriers IAG, easyJet and Ryanair are also unlikely to be takeover targets, said Mr Grant. “They are best in class and very strong, so if anything, they would be candidates for expansion, rather than the other way round,” he said.

However, the dominance of US carriers American Airlines, Delta and United as the “Big Three” of air travel could be challenged by the rise of new carriers and population growth in emerging markets.

OAG’s report - titled The Fight for Global Markets - argues that by 2025, China, Indonesia and Turkey could be the home countries of the world’s three major airlines, as they are helped by their large domestic markets, expanding economies and advantageous geographic positions.

Mr Grant added: “While the target of the US concern has been Gulf carriers, it could equally have been Chinese carriers. Chinese carriers are closing in and within seven years China will have replaced the US as the world’s largest aviation market.”

The fast-growing Gulf-based airlines such as Emirates, Etihad and Qatar are likely to continue to grow, but because not as fast as airlines based in the three countries identified by OAG.