UPDATE 3-United Airlines extends cancellations of Boeing 737 MAX flights into August

CHICAGO/SEATTLE May 24 (Reuters) - United Airlines said on Friday it is extending by one month its cancellations of Boeing Co 737 MAX flights, through Aug. 3, as the jetliner remains grounded following two fatal crashes. United, which operates 14 737 MAX jets, said the decision would lead to about 40 or 45 daily canceled flights. The Chicago-based carrier joins rivals Southwest Airlines Co and American Airlines Group Inc which had already suspended 737 MAX flights into August as global carriers await regulatory approval for the aircraft to fly again.