DALLAS/FORT WORTH, March 18 (Reuters) - AMR Corp.'s (AMR) American Airlines unit said on Monday it would also stop paying base commissions to travel agents, becoming the first carrier to match a move last week by rival Delta Air Lines Inc. (DAL). American, the world's largest airline, said the action is effective today. Like Delta's move, American's decision applies to all tickets issued within the United States and Canada for domestic and international travel. The base commission for travel agents, whittled away for years by the airlines, was most recently 5 percent. ©2002 Reuters Limited.