The prospect of a bumper plane order battle brightened a depressed outlook for plane manufacturers on Thursday as United Airlines was reported to be seeking 150 jets despite fresh warnings of industry losses.

The Wall Street Journal reported that UAL Corp's United Airlines had asked Boeing and Airbus to put forward competing bids for up to 150 new airliners, contrasting with many who are axeing or delaying purchases.

The deal could be worth more than $10 billion for the two aircraft makers, the newspaper said, adding that United sent a formal request to Boeing and Airbus on Tuesday.

Airbus declined comment but shares in parent EADS initially rose more than 2 percent before trimming gains.

Most airlines are shedding capacity to cope with a steep fall in demand and many have deferred orders to conserve cash and in the absence of financing for final delivery payments.

The head of global airlines body IATA told Reuters earlier that plane orders could fall 30 percent in 2010.

The possible contest echoes an epic battle between Boeing and Airbus, then a relative newcomer to the U.S. market, in 1992 at the cusp of another economic and industry recession.

The battle saw United break its reliance on Boeing and opt for dozens of Airbus aircraft for domestic routes. That sparked a rethink that helped push the U.S. planemaker into modernizing its 737 short-haul plane, now the world's most sold aircraft.

United's current fleet of almost 400 aircraft mainly consists of the Airbus A320 single-aisle family for short and medium domestic routes and Boeing wide-body jets such as the 747 and 777 mini-jumbo for longer routes and international travel.

Most U.S. airlines, hampered by frail finances, held back from joining in a boom in plane orders that reached its zenith last year, but many are running fuel-guzzling fleets.

United's order request focuses on replacing many of its 111-airplane wide-body fleet, as well as some of its 97 aging Boeing 757 narrow-body planes, the Wall Street Journal said.

United could sign a major order as early as the fall if Boeing or Airbus agree to certain conditions, the paper said, citing people familiar with the matter.

However, the financing arranged by the manufacturer that does not eat into United's cash would be the most crucial, these people told the paper.

A Fitch credit analyst told Reuters last month that airlines facing the greatest risk of covenant breach that could potentially lead to a liquidity crisis were US Airways, American Airlines parent AMR and United parent UAL Corp.

Such a scenario would only unfold if revenues continued to worsen in the summer and there were no signs of U.S. recovery by late this year, Fitch Ratings analyst Blil Warlick said in early May.

However a Standard & Poor's analyst said most airlines have enough cash to limp through the downturn.

(Reporting by Tim Hepher in Paris, Ajay Kamalakaran and Esha Dey in Bangalore, David Chance in Kuala Lumpur; Editing by David Cowell)