Delta Air Lines early next year will stop flying to Tokyo's Narita International Airport, which for 30 years was the main Asian hub of Minnesota-based Northwest Airlines.

Delta, the dominant carrier at Minneapolis-St. Paul International Airport since purchasing Northwest in 2008, by next spring will complete a shift away from Narita to Haneda International Airport, Tokyo's older, closer-in airport.

Delta started breaking apart the Narita-based hub in 2016 because it lacked a partner carrier in Japan and saw rising demand for flights between the U.S. and other places in Asia. That fall, Delta shifted its daily MSP-Tokyo flight, along with one from Los Angeles, to Haneda.

In the time since, Delta gradually reshaped its transpacific routes with more nonstops from U.S. cities to South Korea and China. It added a direct flight between MSP and Seoul in April this year. And it built a deeper partnership with Korean Air for its passengers starting in the U.S. to connect through Seoul to Asian destinations.

As a result, Delta stopped flying to some major Asian airports, notably Hong Kong, where it ended service last October.

In May, it won preliminary approval from the U.S. Department of Transportation to fly nonstops between Haneda and five other U.S. cities: Atlanta, Detroit, Seattle, Portland, Ore., and Honolulu. It flew nonstops between those cities and Narita previously.

Late last week, Delta announced the final shift away from Narita will soon begin by changing those nonstops and two others, between Narita and Singapore and Narita and Manila.

"Contingent upon the final order from the U.S. Department of Transportation and the ability to secure viable operational slots, Delta intends to transfer its full operation of U.S.-Tokyo services from Narita to Haneda, the city's closest and most convenient airport," the airline said in a statement.

It didn't give precise dates for those changes.

Next month, it will stop flying between Narita and Singapore and, next March, it will halt service between Narita and Manila. Delta will subsequently start a daily round trip between Seoul and Manila. It will rely on Korean Air to take Delta passengers between Seoul and Singapore.

With the move to Haneda, Delta has made Tokyo a single-point destination reached from seven U.S. cities rather than a hub where it would also connect passengers to ongoing flights in its planes to further Asian cities.

Northwest, the first U.S. airline to fly to Tokyo after World War II, started its routes at Haneda in 1947. After the arrival of the Boeing 747 jumbo jet in 1970, Northwest flew directly to several Asian destinations from Minneapolis-St. Paul and Detroit in the 1970s. In 1978, it transferred its Japanese flights from Haneda to Narita, which opened in 1972 and was designed to relieve international traffic from Haneda.

At its peak in the 1980s and 1990s, Northwest flew to about 20 U.S. and Asian cities from Narita and led U.S. airlines in transpacific passenger traffic.