Southwest Airlines Co. will cut about 1,750 jobs in its leadership ranks, a dramatic step to reduce expenses that mark the first layoffs in the carrier’s history.

The pullback will impact 15% of corporate positions, including senior leadership and directors, the airline said in a statement Sunday. The reductions start in late April and will be “substantially complete” by the end of the second quarter.

“This is a very difficult and monumental shift,” Chief Executive Officer Bob Jordan said in a letter to workers. “With the best intentions, the growth of our leadership and noncontract functions have outpaced our operation’s growth for many years.”

The job cuts extend the upheaval that has gripped Southwest for much of the past year, which featured a battle with activist Elliott Investment Management, a board overhaul and significant operational changes. The airline is rethinking its long-held and famous one-size-fits-all business model, and will offer premium seats and some with more legroom after just beginning red-eye flights.

Southwest has long boasted of never having an involuntary layoff over a history stretching back more than five decades, but the carrier has taken steps to rein in its workforce. The company last month paused hiring for management and headquarters jobs, and last year it suspended hiring of pilots and flight attendants. In November, it offered voluntary buyout packages or extended leaves to airport workers in 18 cities, including Los Angeles and Atlanta.