TORONTO (Reuters) - Canada's Bombardier Inc (>> Bombardier, Inc.) has been showing its new medium-range CSeries jet to potential U.S. buyers, a spokeswoman said on Friday, as its test program advances after a summertime halt due to an engine problem.

The Canadian planemaker is interested in showing the aircraft to a number of U.S. mainline carriers, including United Airlines Continental Holdings Inc (>> United Continental Holdings Inc), said spokeswoman Marianella Delabarrera. She declined to say who has seen it so far.

"We're trying to capture as much of the interest as possible," said Delabarrera of the ongoing demo tour. "We really don't want to disrupt the flight testing if we can prevent that, but there are times when it's convenient."

The closely watched CSeries is being tested at Bombardier's facilities in Mirabel, Quebec, and Wichita, Kansas.

In an ambitious push into the competitive commercial jet market, the CSeries aircraft will compete with smaller offerings from Boeing Co (>> The Boeing Company) and Airbus Group NV (>> AIRBUS GROUP) as well as Brazilian planemaker Embraer SA (>> Embraer SA).

Testing was halted in May after an on-ground engine fire, but resumed in September. The program has been plagued by delays and rising costs, worrying investors.

One of the CSeries test planes went to Bombardier's regional sales office in Dallas in October. It also visited Republic Airways Inc (>> Republic Airways Holdings Inc.), a unit of American Airlines Group Inc (>> American Airlines Group Inc) that has a firm order for the CSeries, in Indianapolis.

Delabarrera said some customers went to Dallas to see the plane, and others have visited Mirabel.

(Reporting by Allison Martell; Editing by Jeffreys Hodgson and Benkoe)