U.S. Army pilot Shaun Perez spent ten hours flying an Apache helicopter over Afghanistan, providing gun cover for Special Forces soldiers on the ground as they hunted for high-value targets, guns and weapons.

Returning to his base at dawn, he donned a fresh uniform before shutting himself into a small room to secure the next stage of his career - as a commercial airline pilot.

He would win the job in a video interview that day in August 2017, joining hundreds of other U.S. military helicopter pilots who have taken attractive offers from domestic airlines trying ease a global pilot shortage.

Perez took advantage of one of the tightest labour markets in the United States, created by years of slow hiring, a wave of pending retirements at major U.S. airlines, and Federal Aviation Administration rules that in 2013 increased the number of required training hours from 250 to 1,500.

The industry's aggressive recruitment of military helicopter pilots is one of the most striking examples yet of the contortions required to quickly train new commercial aviators since the FAA increased the minimum flying requirement. The pilot shortage threatens the industry's growth just as travel demand booms.

Airlines have been forced to more than double starting salaries to US$54,000 (41,712 pounds), excluding bonuses, in 2018 from US$21,000 a decade ago, according to aviation consultant Kit Darby.

Perez, 38, now flies under the banner of United Express, the regional branch of United Airlines, at a strong starting salary with his training costs covered.

Ten U.S. regional carriers are offering helicopter pilots like Perez up to US$50,000 to pay for commercial airplane training, and in some cases additional signing bonuses, according to a survey by Reuters.