The parent company of European aircraft maker Airbus (search) Thursday selected four Southern states as finalists for a $600 million U.S. factory to build refueling tankers for the U.S. military.

Sites in Mobile, Ala.; Melbourne, Fla.; Kiln, Miss.; and North Charleston, S.C., will compete for the right to host the U.S. factory, which could begin operations as soon as next year.

The four sites were each asked to provide additional information in a formal request for proposals, which was issued Thursday.

"After careful evaluation, four locations emerged as the sites most capable of meeting the transportation, personnel and manufacturing demands of large military aircraft assembly," said Ralph Crosby Jr., chairman and CEO of EADS North America (search).

"The site we ultimately select will be our partner in creating the U.S. industrial capacity necessary to produce the best, most capable aerial refueling tanker aircraft for the U.S. Air Force," Crosby said.

More than 70 sites from 32 states had responded to a request by the European Aeronautic Defence and Space Co. (search), parent company of Airbus, for information on the bidding process.

Officials from Washington state — where Boeing assembles 737s, 747s, 767s and 777s — were among those attending a February informational session hosted by the company in Washington, D.C.

France-based EADS has said it hoped to build a refueling tanker to compete with the Boeing 767 for a multibillion dollar Air Force contract to replace the aging fleet of Boeing-built KC-135 tankers.

Congress last year nullified a potential $23 billion deal with Boeing amid a growing ethics scandal that has led to guilty pleas by two top Boeing executives. The Pentagon is expected to reopen the deal to competition later this year.

The four sites selected as finalists are Mobile Downtown Airport, Mobile, Ala., Melbourne International Airport, Melbourne, Fla.; Stennis International Airport, Kiln, Miss.; and Charleston International Airport, North Charleston, S.C.

The four finalists will have until the end of May to submit a detailed bid. EADS North America said it expects to select the site by July.

Initially, the company plans an engineering center that would employ 100 to 150 people. If the company wins the Air Force contract, it would then team with a U.S. defense contractor to build the factory, which could employ as many as 1,100 people.

Speculation has centered on a possible partnership with Northrup Grumman Corp. (NOC), but EADS officials have not confirmed that a deal has been reached.