A US Airways tail rests on the tarmac near two American Airlines planes at Ronald Reagan Washington National Airport in Arlington, Virginia on April 23, 2012. - 

American Airlines and US Airways have officially announced their long-suspected merger. Together the companies will become the largest airline in the world, but the consolidation process won’t be without its challenges.

It’s similar to moving in with a new boyfriend or girlfriend -- suddenly there are two couches, two beds, two lives that need to be combined.

Challenge number one will be merging the front-end of these two companies, including airport hubs and flight routes. It includes everything from repainting the outside of planes and standardizing their cabins, to pilots and flight attendants learning new equipment.

“They’ll have to familiarize the American Airlines pilots with US Airways Airbus airplanes, and they will have to familiarize US Airways pilots with the various planes American flies," says Henry Harteveldt, a travel industry analyst with Hudson Crossing.

He says challenge number two will combining the back-end. In the past, airline mergers have had trouble combining reservation systems. And then there’s the issue of company culture.

"US Airways tends to have a thinner management structure and decisions tend to be made a little bit more quickly. American Airlines is more hierarchiacal and they will do analysis after analysis after analysis," says Harteveldt, who adds it could be three or four years until these two airlines are truly one.

Follow Tracey Samuelson at @tdsamuelson