Nov. 4 (Bloomberg) -- United Airlines Inc., the third largest U.S. carrier, filed a trademark infringement lawsuit against Bangladesh-based United Airways Ltd., claiming that its name will confuse customers of the American company.

United Airways plans to expand its air service from Bangladesh and India to markets including the U.K., where United Airlines does business, according to the complaint filed Nov. 2 in U.S. District Court in Brooklyn, New York.

United Airlines, which has more than 3,300 flights a day, said United Airways’ English-language Web site encourages customers to book travel at an office in the Astoria section of New York City, according to the complaint. United Airlines told the Bangladesh carrier in 2007 to stop using its name and found out just this year about the sales office in New York, according to the complaint.

Representatives of United Airways in Bangladesh couldn’t be reached for comment after regular business hours there. A representative at Jumbo Travel, reported in the lawsuit to be the sales office for United Airways in Astoria, referred questions to a phone number in the U.K. and a call there wasn’t returned.

United Airlines has no comment beyond what’s in the lawsuit, said spokesman Michael Trevino.

UAL Corp., United Airlines’ Chicago-based parent, fell 18 cents, or 2.7 percent, to $6.46 in Nasdaq Stock Market trading at 4:29 p.m. in New York. The shares have fallen 41 percent this year.

The case is United Airlines Inc. v. United Airways Ltd., 09-04743, U.S. District Court, Eastern District of New York (Brooklyn).

To contact the reporter on this story: Don Jeffrey in New York at djeffrey1@bloomberg.net.

Last Updated: November 4, 2009 16:37 EST