Virgin America is officially Alaska Airlines, at least according to air traffic controllers.

The airlines merged just over a year ago, but the deal was sealed in the eyes and ears of air traffic controllers Thursday when Virgin America lost its colorful call sign that conjures up its California roots: "Redwood."

A call sign is what pilots, air traffic control and other ground personnel use to address airlines. On Thursday, Virgin America flights adopted Alaska Airlines' simpler call sign, "Alaska," because the two airlines will operate under what's known as a "single operating certificate."

"It's like changing your name if you get married," said Phil Derner, a former airline dispatcher and founder of NYCaviation.com, an aviation news and plane-spotting website.

The Federal Aviation Administration announced the name change last month.

"Redwood" is just one of several colorful call signs used by airlines. British Airways is known as "Speedbird," which refers to an early airline logo. Angolan cargo airline Gemini is known as "Twins."

An air traffic controller would use the call sign and flight number to address the pilots — for example, "Speedbird 1516."

US Airways used "Cactus," a holdover from America West, an Arizona-based carrier it merged with in 2005. US Airways later merged with American Airlines, whose call sign is simply "American." Delta is "Delta," and United is "United."

Alaska is in the midst of marrying its fleets and crews with those of Virgin America, which began flying in August 2007. Passengers can still book flights on the Virgin America website and fly on its planes.

Good night, Redwood.