There are three main alliance groups in international aviation. Here are some of the main players behind these associations.
With 27 members, Star Alliance is the largest airline group. It was the first global airline alliance, founded in 1997 by Lufthansa, United, Air Canada, Thai Airways and Scandinavian Airlines.
Since then it has added airlines in Latin America, Asia and Australia, and today the grouprepresents more than 21,000 daily departures, and more than 1,100 airports in 181 countries. Taken together, annual passenger volumes exceed 600 million.
In 1999, two years after the creation of Star Alliance, competing airlines rushed together to form their own group called oneworld.
Led by American Airlines, British Airways, Qantas and Cathay Pacific, there are now 19 airlines in the group, with Kingfisher Airlines of India and Air Berlin expected to join in the next 12 months. Like all alliances, some members have chosen to leave through the years, including Aer Lingus, which changed its business strategy, while others went out of business, including Canadian Airlines and Air Liberte of France.
The smallest of the three alliances, SkyTeam, has 13 member carriers and is led by Air France-KLM and Delta. The group was formed in 2000.
"The benefits of an alliance outweigh the costs and complexities of an intercontinental merger," Leo van Wijk, the chairman of SkyTeam, said recently. Its two newest members are Vietnam Airlines and TAROM of Romania. China Eastern plans to join the group later this year along with two other unnamed carriers that are targeted for induction, the group says.