WASHINGTON (AP) _ All Nippon Airways, Japan's largest domestic airline, will buy 11 Boeing 747 jumbo jets for $1.56 billion to expand its international routes, including planned increased service to the United States.

Executives of All Nippon and the Boeing Co. announced the purchase at a Washington news conference Tuesday, saying the new aircraft are to be delivered between next July and late 1992.

Akio Kondo, deputy president and chief operating officer for the airline, said it will decide later whether to buy the 200-series jumbo jet or the more technologically advanced 400 series, which is still under development.

''We'd like to buy 400s,'' Kondo said through an interpreter after the announcement. But he said the airline first must persuade its pilots to go along with using only two crew members to fly the planes.

The Boeing 747-400, which relies heavily on computers and is scheduled to come off the assembly line in late 1988, is expected to be certified for a two-member crew. Three crew members are required on all other Boeing 747s, including the 200 series aircraft.

The new 747-400 model, which can carry nearly 500 passengers, is being built for extra long range and fuel economy. It also is billed as being a cost-saver because it will be the first of the jumbo jets not to require three cockpit crew members.

All Nippon hopes to use the new airplanes for aggressive expansion of its international business. Last July it began non-stop service between Tokyo and Washington and Los Angeles. The airline plans to increase its flights on the U.S. routes and is seeking permission to expand service to other U.S. cities. It also plans to broaden its service to Europe.

Boeing chairman T.A. Wilson called the deal the latest in ''a close and fruitful relationship'' between the U.S. manufacturer and All Nippon. Each of the planes is worth ''in excess of $100 million,'' excluding engines and spare parts, officials said. They said no decision has been made on which manufacturter - General Electric, Pratt & Whitney or Rolls Royce - will provide the engines.

It is the second major order of Boeing aircraft by All Nippon Airways in a year. Last December the airline agreed to buy 25 Boeing 767 aircraft for $2.36 billion. It already is flying about 100 Boeing jetliners.

Boeing, which is based in Seattle and holds about two-thirds of the world's large jetliner market, also recently announced agreement to sell Japan Air Line five Boeing 747s and six smaller 767s for $870 million.

The latest order from All Nippon and the earlier deal with JAL, which is Japan's government-owned carrier, represents a rebound for Boeing, which was stung Oct. 1 with the announcement that Northwest Airlines had agreed to buy as many as 100 jetliners from Airbus Industrie, the European consortium. Northwest plans to buy 150-seat A320 models not yet off the assembly line.

If all of those planes are sold the deal would amount to $3.2 billion for the manufacturer, which is owned by France, West Germany and Great Britain.