Delta Air Lines Inc. (DAL) has intensified efforts to freeze financial support by a U.S. government agency for Boeing Co. (BA) aircraft exports, this time drawing in one of its own alliance partners as one of five carriers alleged to gain an unfair competitive edge from the system.

The airline filed a new lawsuit calling on the Export-Import Bank of the U.S. to halt the planned provision of loan guarantees to the five carriers, backed in its latest challenge by the parent of Hawaiian Airlines and the main U.S. pilots' union.

Previous efforts led by Delta and other U.S. carriers to restrict Eximbank's aircraft support haven't hampered Boeing sales, but the new suit filed late Wednesday targets more carriers, including Korean Air Lines Inc. (003490.SE).

The suit, filed on the eve of Eximbank's annual conference, also targets proposed guarantees for Dubai's Emirates Airline, Abu Dhabi-based Etihad Airways, Latam Airlines Group SA and LOT Polish Airlines.

Korean is a member of the SkyTeam global marketing alliance alongside Delta, and among dozens of airlines that use loan guarantees from export credit agencies to help finance Boeing and Airbus planes, as well as jets made by Bombardier Inc. and Embraer S.A.

Delta, Hawaiian and the Air Line Pilots Association said in their suit that the loan guarantees from Eximbank provide overseas carriers cheap funding unavailable to U.S. carriers, though didn't quantify the alleged benefit. They contend this leads to lost jobs in the U.S. airline industry.

Boeing and other critics of the efforts to change or dilute Eximbank's support point to the thousands of aerospace jobs that rely on exports.

Atlanta-based Delta and its co-litigants also said the Eximbank financing would help the named airlines expand service to the U.S. Delta didn't mention that it has a code share with Korean on flights to and from the U.S., allowing the carriers to sell seats on each others' flights. Korean wasn't immediately available for comment.

Delta was part of a larger group of U.S. carriers that unsuccessfully sued Eximbank in 2011 over its support for loan guarantees on Boeing jets bought by Air India. That case is under appeal.

The move did stir Republic-led efforts that stalled the renewal of Eximbank's charter last year before it was extended until September 2014 with a provision that the bank carry out deeper economic-impact studies on the effect of its support on U.S. jobs.

Eximbank declined to comment.

Delta and its co-litigants contend in a suit filed in February that Eximbank hasn't conducted such thorough studies.

Export-credit agencies generally don't provide support for deals involving companies in their own countries, though Atlas Worldwide Inc., a big U.S. cargo airline, has bought Boeing jets with Eximbank guarantees.

The rules governing support for aircraft deals from agencies in the U.S., Europe, Brazil and Canada were also reformed, making their guarantees more expensive since the start of the year.

Write to Doug Cameron at doug.cameron@dowjones.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires

(END) Dow Jones Newswires

04-04-13 1655ET