The global alliance which represents heavyweight airlines Cathay Pacific, British Airways, American Airlines and Qantas has rolled out customer service upgrades to try and stop frequent fliers defecting to rivals.

Technology improvements and information sharing to enhance the user experience aim to persuade 225 million customers of the 13 member airlines in the Oneworld alliance to stick with those carriers.

Travellers flying with more than one airline in the same journey will only need to check in, obtain all boarding passes and access their itinerary from one carrier online to simplify the experience.

Eight million customers embarked on a multi-ticket journey in the past year.

Oneworld is also working on improvements to the customer experience at major airports, which will include alliance-branded lounges. CEO Rob Gurney described the changes as a relaunch of the alliance on its 20th birthday.

Trips involving more than one airline were previously a hassle as passengers commonly needed to use multiple airline apps to access details of each flight. The tech upgrades will mean Cathay customers being able to use the company's website or app to access any booking with a Oneworld partner, doing away with the need for login details with each airline.

Oneworld is formed of 13 airlines and 30 affiliate carriers and celebrated its 20th birthday in London on Friday, where it unveiled a raft of changes.

The grouping is one of three global airline pacts. The others are Star Alliance, which counts Singapore Airlines as a top member, and Skyteam, which has Delta Air Lines.

"We are effectively relaunching Oneworld, and it's designed to have relevance for stakeholder groups, our customers and our member airlines," Gurney said.

Cathay and Qatar Airways are the first pairing to have started using new digital functions that enable the upgrades.

Cathay CEO Rupert Hogg told an audience in London that Oneworld was on the right path to keep the grouping relevant and contemporary. The three alliances have increasingly become less important as airlines prefer to partner with carriers outside their alliances where it makes sense for business. Questions have been asked about their future with the strength of budget and non-alliance airlines.

These problems were acknowledged by Willie Walsh, CEO of International Airlines Group, the parent company of British Airways.

"For this alliance to stay relevant in an ever-changing world, we have got to change and evolve," he said.

Oneworld-branded lounges are also being planned - at least three by 2020 - to boost the alliance's appeal, especially at airports where there is no home carrier with the alliance. Proposed locations are being narrowed down to airports where the grouping and its members have proposed sharing check-in desks to improve service quality.

Oneworld said the new Beijing Daxing International Airport, due to open later this year, was a good opportunity. Ten members currently fly to Beijing operating 175 flights a week.

"We've been engaged in discussions with the Chinese authorities and the airport operators about co-locating in the new airport. Not every airline will be there. But we believe we will have a critical mass of Oneworld airlines," Gurney said.

The alliance's members currently serve 1,110 airports in 180 territories, with 14,000 daily flights carrying 550 million passengers annually on a fleet of 3,500 aircraft.