Continental Airlines (CAL) on Tuesday officially joined the Star Alliance, ending a long-standing relationship with the SkyTeam alliance, whose lead member is now Continental’s biggest competitor, Delta Air Lines (DAL).

Continental’s long anticipated switch to Star Alliance brings the airline into a pairing with 23 other worldwide airlines, including Chicago-based United Airlines (UAUA). Continental will now provide code share agreements with the 23 other airlines, along with sharing passenger benefits program like frequent-flyer miles and airport lounges.

“Our membership in Star Alliance positions us to deliver a broader network to our customers, and to achieve better business results and a stronger future for my co-workers, our customers and communities as a result of the benefits from participating in the world's largest airline alliance,” said

Larry Kellner, Continental's CEO, in a statement.

Continental estimates its partnership with Star will generate $100 million in additional yearly revenue, and expects the alliance will boost the company’s profit by 2011.

Continental’s switch to the Star Alliance from SkyTeam was considered by some industry analysts as a “soft” merger between Continental and its Chicago partner United. Last year when Delta merged with Northwest Airlines, Continental had considered a merger with United but that process fell through after the airlines could not reach an operational agreement.

However because of Delta’s merger, Continental no longer wanted to be in an alliance with Delta.

"You want an alliance with someone who is not a competitor," Continental President Jeff Smisek told the Wall Street Journal in an interview.