Alaska Airlines has closed its acquisition of Virgin America to become the fifth-largest airline in the U.S.

Seattle-based Alaska and San Francisco-based Virgin America plan to spend the next year trying to obtain Federal Aviation Administration certification to allow the two airlines to operate as a single carrier.

Both airlines offer daily flights between Hawaii and the mainland.

“Alaska Airlines and Virgin America are different airlines, but we believe ‘different’ works — and we’re confident fliers will agree,” said Brad Tilden, CEO of corporate parent Alaska Air Group. “Together, we’ll offer more flights, with low fares, more rewards and more for customers to love, as we continue to offer a distinctive travel experience. The two airlines may look different, but our core customer and employee focus is very much the same.”

Alaska said no decision regarding the Virgin America brand has been made and that Alaska plans to continue to operate the Virgin America fleet with its current name and product for a period of time while it conducts extensive customer research to understand what fliers value the most.

Virgin America will continue to fly under its brand with no immediate changes to the onboard product or experience.

Starting Monday, Virgin America Elevate members and Alaska Airlines Mileage Plan members can earn rewards on each other’s flights and will be able to purchase Virgin America tickets at alaskaair.com that same day. Tickets will continue to be available for sale at virginamerica.com for the immediate future.

Beginning Jan. 9, Virgin America Elevate members will be invited by Alaska Airlines to activate new Mileage Plan accounts.