(Adds details, background on cancellations)
CHICAGO, June 13 (Reuters) - Southwest Airlines Co said on Thursday it would keep the Boeing Co 737 MAX jet off its flying schedule through Sept. 2, as the timing of the return of the troubled airplane to service remained uncertain.
Southwest, the largest global operator of the MAX with 34 jets, had previously said it was canceling flights through Aug. 5.
The Federal Aviation Administration said on Wednesday it did not have a specific timetable on when the 737 MAX jet would fly again, after two fatal crashes led to the airplane's worldwide grounding in March.
The revision will proactively remove about 100 daily flights from its schedule, out of a total peak-day schedule of more than 4,000 daily flights, the low-cost carrier said in a statement.
(Reporting by Tracy Rucinski Editing by Bernadette Baum)