A consortium including European plane maker Airbus has clinched a lucrative US contract to build planes designed to refuel US military jets.

The £20 billion deal to replace aging KC-135 air tankers was clinched by Northrop Grumman corp and Airbus who saw off stiff competition from rival manufacturer Boeing. The news comes as a blow to Boeing that was looking to replace the planes they provided in the 1950s with their new model.

Boeing, which manufactures the 767 commercial airliner, has said it was disappointed with the decision and has sought information from the US military into its decision. While the airforce insists that the better offer was accepted, news of the deal has resulted in protests from US lawmakers who fear that the move could harm the US economy and cost American jobs.

In a joint statement, a delegation of Washington senators and congressmen said: “We are outraged that this decision taps European Airbus and its foreign workers to provide a tanker to our American military. This is a blow to the American aerospace industry, American workers and America’s men and women in uniform.”

However senior air force officials have defended the decision saying that the selection process was fair and that the best offer was chosen.

Speaking about why the Northrop Grumman corp was awarded the contract, General Arthur J Lichte said: “I can sum it up in one word: more. More passengers, more cargo, more fuel to offload, more [battle casualties] it can carry, more availability, more flexibility and more dependability,” he added.