Alaska Airlines closed its acquisition of Virgin America on Wednesday and quickly sought to persuade travelers the duo belongs together, using cheeky messages like “salt and caramel was an unlikely combo, too.”

“We’re an odd couple that works well together,” Alaska said on its merger website, differentworks.com. “We may seem like an unexpected pair—but our differences complement each other.”

The new Alaska is now the nation’s fifth-largest airline, but though the two carriers will combine some customer-facing functions quickly, they will operate separately for the foreseeable future. It should take at least one year before the two airlines operate under a single operating certificate, a Federal Aviation Administration designation required before Virgin America and Alaska can fly as one entity.

While Virgin America’s certificate will eventually disappear, Alaska continues to play it coy when it comes to the startup airline’s brand. Alaska CEO Brad Tilden said the company will make a decision early next year, after it researches what flyers like about Virgin America. For at least the next 12 months, little will change aboard Virgin America’s planes.

Alaska would prefer not to alienate any of Virgin America’s loyal customers in San Francisco and Los Angeles, who have come to appreciate the nine-year-old carrier’s quirky culture and passenger-friendly amenities, such as the ability to order food from the seat-back entertainment screen.

“This is a big decision and one that deserves months of thoughtful and thorough analysis,” CEO Brad Tilden said in a statement regarding the future of Virgin America’s brand.

The first changes will come next week. Starting Dec. 19, customers will be able to buy tickets on Virgin America’s website for travel on Alaska. Also, the two airlines will tie together their frequent flyer programs, so travelers may earn points on both carriers, and elite frequent flyers will receive priority boarding and check-in on both Alaska and Virgin America. However, in the near-term, the two frequent flyer programs will operate independently.

As part of its announcement, Alaska said it would bulk up its new San Francisco hub. Next December, it plans to add three more routes — to Orlando, Orange County and Minneapolis. Alaska has been a minor player in San Francisco, but with the acquisition it will be the airport’s second-largest airline, behind United Airlines.

Photo Credit: Alaska Airlines has a new irreverent campaign to celebrate its acquisition of Virgin America. Alaska Airlines