Thursday, April 24th, 2003 7:55pm Easter Daylight Time American Air CEO Donald Carty Resigns By DAVID KOENIG, AP Business Writer FORT WORTH, Texas - The chairman and chief executive of American Airlines resigned Thursday as labor leaders and negotiators for the carrier agreed to a sweetened package of cost cuts in an effort to keep the company out of bankruptcy. Gerard Arpey, the company's president, will replace Donald J. Carty as CEO, while board member Edward A. Brennan will take over as chairman.