WASHINGTON, March 21 (Reuters) - The CEOs of American

Airlines ( AAL ), United Airlines, Visa and Mastercard ( MA ) will

not testify at an April 9 hearing on credit card competition,

the chair of the Senate Judiciary Committee said Thursday.

Senator Dick Durbin in February invited the executives of

the firms that have fought his legislation seeking to reduce

fees charged by Visa and Mastercard ( MA ) on transactions. "They're

just too darned busy to come and explain the major source of

profits for their businesses," Durbin said.