WASHINGTON -- State lawmakers want answers and an investigation as to why Boeing lost out on one of the biggest defense contracts in history.

Boeing was an apparent frontrunner to build the next generation of mid-air refueling tankers for the Air Force. The decision came down Friday that Northrop Grumman and Boeing’s European rival Airbus swooped in and won $40 billion dollar contact.

"It's just a disaster," said Rep. Norm Dicks, D-Wash., one of Boeing's biggest supporters in Congress. "I'm extremely disappointed," Dicks said. "It's just one of the worst things in my whole life. I am just shocked over this."

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Gov. Chris Gregoire called the Air Force decision unfortunate for Boeing and the state of Washington.

"Boeing and its workers build the best planes in the world. They will continue to enjoy great success with their 787 Dreamliner and other innovative products still to come," she said, calling the Chicago-based company a valued corporate citizen of the state.

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Boeing has been supplying refueling tankers to the Air Force for nearly 50 years and had been widely expected to hang onto that monopoly, could protest the decision, though the company said no decision has been made.

Air Force officials offered few details about why they choose the Northrop-EADS team over Boeing since they have yet to debrief the two companies. But Air Force Gen. Arthur Lichte said the larger size was key. "More passengers, more cargo, more fuel to offload," he said.

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The Northrop-EADS refueling tanker, the KC-45A, "will revolutionize our ability to employ tankers and will ensure the Air Force's future ability to provide our nation with truly global vigilance, reach, and power," Air Force Gen. Duncan J. McNabb said in a statement.

Boeing, the state's largest private employer, would have built the tankers, based on its 767 jetliners, at Everett, Wash.

Boeing believes it offered the best value and lowest risk, said Boeing spokesman Jim Condelles.

The EADS/Northrop Grumman team plans to perform its final assembly work in Mobile, Ala., although the underlying plane would mostly be built in Europe. And it would use General Electric engines built in North Carolina and Ohio.