Southwest Airlines Co.'s pilots don't expect to see Boeing Co.'s 737 Max resume flights until February "at least," given work still to be done in a process fraught with safety concerns and politics.

That's well beyond the Jan. 6 date the carrier has set for the grounded plane to be back in its schedule. But ending a global flying ban, enacted in March after two fatal crashes, probably will be delayed by the "many official processes and events" that must take place among regulators globally, Jon Weaks, head of the Southwest Airlines Pilots Association, said Monday.

Southwest is the largest operator of the Max, and the union recently sued Boeing for at least $115 million in lost pay through the end of this year from the grounding — which according to the pilots has caused 30,000 flight cancellations at the Dallas-based carrier. The company has said that parking its 34 Max planes and not getting new ones scheduled for delivery this year has cut at least $225 million from operating income.