NEW : Air traffic controllers ' group says problem will be persistent throughout day . American Airlines spokesman Tim Smith said that 300 to 500 flights had been delayed , virtually every one scheduled for takeoff . NEW : FAA has officials trying to pinpoint cause of computer system failure . ` ` I ' m frustrated . I have to be somewhere , '' delayed passenger says . Air system not compromised , FAA says .
NEW : Air traffic controllers ' group says problem will be persistent throughout day . NEW : FAA has officials trying to pinpoint cause of computer system failure . ` ` I ' m frustrated . I have to be somewhere , '' delayed passenger says . Air system not compromised , FAA says .