The Delta-Northwest merger hasn't been approved, but officials of Atlanta's Hartsfield-Jackson International Airport are beginning to behave as if it's a done deal.

Officials of the city-run airport on Wednesday got initial approval to expand one of Hartsfield-Jackson's five runways in anticipation of more international flights once the merger is approved.

The runway expansion means Hartsfield-Jackson would be able to handle more 400-passenger Boeing 747s, specifically 747-400s, the workhorse of Northwest Airlines' international fleet.

"We expect more large aircraft to be moved here from Detroit [after the merger]," airport Deputy General Manager Mario Diaz said in an interview after the City Council's Transportation Committee gave its nod to spend $3 million for the design phase of the runway expansion.

Atlanta-based Delta Air Lines and Minnesota-based Northwest have agreed to merge and form the world's largest airline, to be called Delta and headquartered in Atlanta. Federal regulators and shareholders have to approve the deal, which could close by year's end.

Detroit is a major hub for Northwest and is a jump-off point for many of its international flights.