Continental Airlines and United Airlines announced they have reached an agreement to tie their networks and operations worldwide. The move comes after the two air carriers flirted in April with the idea of merging, but in the end they decided it’s best not to.

According to the deal reached by the two companies, Continental will renounce its membership in the SkyTeam alliance as it plansto join the rival Star Alliance, the world’s largest group of airline partners. United is already a member of the Star Alliance.

The alliance between the two air carriers and the Continental’s migration to the Star Alliance would require approval from federal regulators.

The agreement was signed on Tuesday in Chicago where Glenn F. Tilton, the chief executive of United, and Lawrence W. Kellner, who runs the Houston-based Continental, met.

The agreement will “provide substantial new opportunities for all of our customers,” said Kellner.

For the passengers, the deal means that one can book tickets on either carrier, earn credit in each other's programs and redeem miles on each carrier. However, nothing changes for the time being. It will take the Continental at least a year to get the approval from the regulators and to get out from existing alliances with Sky-Team and Delta and Northwest airlines.

Besides United, the Star Alliance also includes other big air carriers such as Air Canada, Lufthansa of Germany, Singapore Airlines, ANA of Japan and Air China, and many more.

The alliance offers nearly 18,000 daily flights to 965 destinations in 162 countries.