European planemaker EADS won't be making its own bid to build aerial tankers for the U.S. Air Force, the company said today in the wake of an announcement from its U.S. partner, Northrop Grumman, that it was opting out of the contest.

That leaves Boeing as the sole potential bidder for the $40 billion Air Force refueling plane contract.

EADS' subsidiary Airbus was going to furnish a version of its A330 commercial jet as the basis for its tanker.

Northrop Grumman said the Air Force's new specifications favored a smaller plane like Boeing's over its larger aircraft. Boeing plans to bid a militarized version of its 767 twin jet. That plane would be built in Everett and military features would be added at Boeing's plant in Wichita, Kan.

The initial contract calls for 179 planes. The military could seek follow-on orders for dozens more. Foreign governments could also seek new tankers from Boeing.