According to China Eastern Chairman Liu Shaoyong, the two carriers will extend their cooperation to some key areas such as code sharing.

"That means, when passengers take flight from China Eastern, they will also be receiving service from China Airlines," Liu added.

The two airliners' cooperation can be traced back to January 2003, when they provided service for the first charter flight across the Taiwan Straits for the Chinese New Year.

In addition, their cooperation will also boost the service quality of flights across the Straits during the World Expo, which runs from May 1 to October 31, Liu said.

In recent years, cross-strait trade and passenger numbers have grown rapidly.

A total of 5.41 million passengers traveled between Taiwan province and the mainland over 2009, up 16.3 percent year-on-year.

About 3.12 million passengers chose to travel by air, and the mainland airliners handled 1.23 million passengers, up 590 percent over 2008.

In 2009, China Eastern flew 425,000 passengers to and from the mainland to Taiwan, up 524.4 percent from a year earlier.

China Airlines currently flies to 89 destination cities in 29 countries, and has a fleet of 66 aircraft, including 46 passenger jets and 20 freighters.

Meanwhile, speculation is rife on which of the world's three airline alliances will win China Eastern's favor.

Currently the Shanghai-based carrier is the last of the nation's three major airlines without membership in any alliance.