WASHINGTON (Reuters) - A top Boeing Co (>> The Boeing Company) official on Thursday said a fresh drive by some lawmakers and interest groups to scrap the Export-Import Bank of the United States would put the nation at a competitive disadvantage and risk thousands of U.S. jobs.

Boeing Chief Operating Officer Dennis Muilenburg told an aviation summit hosted by the U.S. Chamber of Commerce that the bank's financing helped offset subsidies and credit financing provided by other governments to its foreign competitors.

"Without it, U.S. exporters would be at an even greater disadvantage in global markets than they find themselves in today," Muilenburg said. "Discarding this important tool for U.S. companies would amount to unilateral disarmament."

The Ex-Im Bank facilities loans to overseas companies to help them buy U.S. products.

Some conservative Republicans have a philosophical objection to the U.S. government running a bank that makes loans to help exporters and have been trying to shut it down for years. They are expected to try again when the bank is up for funding renewal by the end of September.

Heritage Action, the lobbying arm of the conservative Heritage Foundation, this week called the bank a "model of special interest-fueled cronyism.

The bank supports loans on products ranging from lumber to cosmetics but giant corporations such as Boeing, Caterpillar (>> Caterpillar Inc.) and General Electric (>> General Electric Company) are major beneficiaries.

Delta Airlines (>> Delta Air Lines, Inc.) has long argued that Ex-Im Bank financing allows foreign competitors to buy Boeing planes on better credit terms than it can obtain.

Supporters argue that the bank is self-sustaining, and contributes to federal coffers since it earns money on fees and interest.

In fiscal 2013, the bank authorized $27 billion to back about $37 billion in U.S. export sales and returned over $1 billion to the U.S. Treasury.

Muilenburg said the loss of the credit financing provided by the Ex-Im Bank meant foreign carriers might buy aircraft from Airbus (>> AIRBUS GROUP) or others rather than from Boeing.

"Given the hundreds of thousands of American jobs the bank supports every year and the billions of dollars we generate for taxpayers, we are optimistic Congress will reauthorize the Bank as soon as possible," said Daniel Reilly, a bank spokesman.

Loren Thompson, a Virginia-based defense consultant, said support from lawmakers keen to protect jobs in their districts meant the Ex-Im Bank would probably survive.

(Editing by Ros Krasny and Alden Bentley)

By Andrea Shalal