Southwest Airlines is cutting thousands of jobs in the company’s first-ever mass layoff.

The Dallas-based airline plans to cut 15% of its corporate workforce or approximately 1,750 jobs, in an effort to minimize costs.

In a letter from Southwest President and CEO Bob Jordan to employees, he says the company is carrying out its three-year business plan to transform Southwest Airlines.

Our transformational plan is the largest and most comprehensive in our 53-year history, and it focuses on three simple but powerful objectives. First, boost revenues and loyalty by offering our Customers the experience they want; second, maximize efficiencies and minimize costs; and third, make the most of our investments. As we continue to work together to transform our Company, an area of intense focus will be maximizing efficiencies and minimizing costs. We must ensure we fund the right work, reduce duplicative efforts, and have a lean organizational structure that drives clarity, pace, and urgency. Improving how we work together and how we get work done has a tremendous impact on our efficiency as a Company and how we deliver against our plan. We have made the very tough decision to move forward with a reduction in our workforce, focused almost entirely on Corporate and Leadership positions.

Southwest says the layoffs won’t begin until late April.