Alaska Air Group on Wednesday completed its $4 billion acquisition of Virgin America, about a week after the deal gained U.S. Justice Department approval and Alaska settled a lawsuit filed by private plaintiffs seeking to block the merger on antitrust grounds. Alaska added that it and Virgin America will spend the next year working to secure Federal Aviation Administration (FAA) certification to allow the two airlines to operate as a single carrier, while Alaska Air Group sister carrier Horizon Air continues to operate on its own certificate.

The combination expands service most notably in San Francisco, Los Angeles and Seattle. Together, the airlines offer 289 daily flights to 52 destinations from California, including 113 daily nonstop flights to 32 destinations from three San Francisco Bay Area airports and 105 daily nonstop flights to 37 destinations from four Los Angeles area airports. It also opens growth opportunities on the East Coast by increasing Alaska Air Group’s access to slot-controlled Reagan National in Washington, D.C. and the three primary New York City-area airports, namely at JFK, La Guardia and Newark. The company also announced new flights from its San Francisco hub to Orlando, Minneapolis and Orange County, California, beginning next summer.

Although the Department of Justice (DOJ) did not require Alaska to divest any assets as a condition of the approval, the airline did agree to make what it called limited changes to its code-share agreement with American Airlines. Specifically, the agreement requires Alaska to end code-share operations with American on some 20 routes where AA and Virgin America compete directly. However, the DOJ did not require changes to any other agreements between Alaska and American, including interline or reciprocal loyalty agreements, or any of Alaska's other airline partnerships, said the airline. The combined airline will now operate 1,200 daily departures from hubs in Seattle; San Francisco; Los Angeles; Anchorage, Alaska; and Portland, Oregon. It will fly some 280 aircraft, including regional airplanes, averaging 8.5 years of age.

“Alaska Airlines and Virgin America are different airlines, but we believe different works—and we’re confident fliers will agree," said Alaska Air Group CEO Brad Tilden. “The two airlines may look different, but our core customer and employee focus is very much the same.”

The merger creates the fifth largest airline in the U.S., offering what Alaska characterizes as “an attractive alternative to the ‘Big 4,’” which constitutes 84 percent of the domestic market.

The company said it has made no decisions on the future of the Virgin America brand. It will continue to operate Virgin America under its current name while it conducts customer research to determine the best course of action, it added. Tilden said he expects to announce a decision early next year.

While Tilden continues to lead the combined company as CEO, Alaska president and COO Ben Minicucci becomes CEO of Virgin America. Peter Hunt, previously Virgin America senior vice president and chief financial officer, will serve as president of the Virgin America subsidiary.