WASHINGTON, Sept 29 (Reuters) - The chief executives of

low-cost carriers Allegiant Airlines and Frontier

Airlines will testify before a U.S. Senate Judiciary

antitrust subcommittee on Tuesday on air carrier competition,

congressional aides said.

Allegiant Airlines CEO Greg Anderson and Frontier Airlines

CEO Barry Biffle are among the witnesses that will testify, as

will Sharon Pinkerton, a senior vice president at Airlines for

America, which represents United Airlines, Delta Air

Lines ( DAL ), American Airlines ( AAL ), Southwest Airlines ( LUV )

and others.