Alaska Air Group Inc. (ALK) renewed its request that the U.S. Department of Transportation open its review of Virgin America's citizenship status to public scrutiny and comment.

The filing Friday by the parent of Alaska Airlines comes after it filed two petitions earlier this year requesting a public inquiry into whether Virgin America Inc. complies with U.S. foreign ownership and control restrictions on U.S. carriers.

"Alaska makes this request to ensure DOT holds all airlines to the same standard of compliance with U.S. law," said the carrier's General Counsel Keith Loveless.

Virgin America started operations in 2007 after a delay in securing regulatory approval linked to its ownership structure. To comply with U.S. law, 75% of the voting stock must be held by U.S. citizens. Virgin America is the creation of British entrepreneur Richard Branson, whose Virgin Group owns 25% of the airline.

The latest filing by Alaska Airlines, which competes with Virgin America on West Coast routes, points out that the company hasn't refuted news reports in March that its U.S. shareholders disposed of their financial interest in the airline.

Virgin America has said it complies with the law and the DOT is aware of its potential changes. The airline has been seeking alternative investors after two private-equity groups that provided the initial capital opted to trigger a sale clause. The airline hasn't said whether U.S. investors retained an "economic interest" alongside board representation, which its opponents said was critical to meet the citizenship test.

Requests similar to Alaska's to the DOT have been made by Sen. Patty Murray, D-Wash., chair of a Senate transportation subcommittee, and Rep. James Oberstar, D-Minn., chair of the House Transportation and Infrastructure Committee, as well as by groups of pilots, flight attendants and aircraft mechanics.

-By Kathy Shwiff, Dow Jones Newswires; 212-416-2357; Kathy.Shwiff@dowjones.com