WASHINGTON (AP) — An industry forecast that nearly half a million new airline pilots will be needed worldwide over the next 20 years as airlines expand their fleets has raised safety concerns that airlines will hire lower caliber pilots as they struggle to fill slots.

Boeing, one of the world’s largest makers of commercial jetliners, forecasts about 460,000 new pilots will be needed worldwide between now and 2031 as global economies expand and airlines take deliveries of tens of thousands of new commercial jetliners. The forecast includes 69,000 new pilots in the North America, mostly in the U.S. The greatest growth will be in the Asia-Pacific region, where an estimated 185,600 new pilots will be needed.