Continental Airlines formally sought permission from the US government on Wednesday to join the Star Alliance.

In a filing with the Transportation Department, the group also sought immunity from antitrust restrictions on scheduling, fares and service.

Joining Star and executing a separate domestic code share with United would strengthen the alliance's East Coast presence with US Airways in Philadelphia, Washington Reagan National, and Charlotte, United at Washington Dulles and Continental in Newark.

The move for an alliance comes after Continental this spring opted against a merger with United, which subsequently decided not to merge with US Airways.

Continental chose to exit the SkyTeam alliance after Delta Air Lines and Northwest Airlines proposed their merger this spring. Those carriers hope to close the deal by year's end, pending antitrust approval.