Woranate Laprabang, chief executive of Vietjet Thailand, said that more than half of Thai pilots cannot return to work because they are unable to renew their licences, reports the Bangkok Post.
Pilots are required to regularly operate flights to maintain their type rating and must undergo annual medical check-ups.
As only 20-30% of pilots have been recalled by airlines, few are available to fly in the aviation sector at the moment, he said.
Vietjet Thailand operates 18 aircraft and employs around 180 pilots. Each narrow-body plane requires 10 pilots to operate.
The airline plans to retire four planes and receive nine new ones this year, requiring it to hire an additional 50 pilots, said Mr Woranate.
He said the airline has already accepted 20 student pilots and plans to recruit another 30 in the second phase.
By 2028, Vietjet Thailand aims to have 50 aircraft in its fleet and a total of 500 pilots.
With 320 new pilots needed over four years, one-third are expected to be student pilots, with the rest from the existing pilot job market.
Mr Woranate said all Thai carriers are expected to develop their own pilots to support capacity growth.
Vietjet Thailand is reportedly using a pay-to-fly scheme, which collects training fees from pilots in exchange for employment, a common practice in Europe, he said.
Teerawat Angkasakulkiat, president of the Thai Pilots Association, said there are two groups of unemployed pilots in Thailand: those with commercial pilot licences but no experience flying for commercial airlines, and those laid off during the pandemic that have stayed out of cockpits.
He said both groups must undergo new training to re-enter the workforce, which requires substantial spending.
If airlines do not cover these costs and pilots are unwilling to pay, employment will not occur.
He said that if an airline receives new planes that match the model of another carrier, job relocations may happen, as pilots trained on specific aircraft types require shorter and less costly training.
Airlines losing pilots must find replacements and often impose pay-to-fly conditions.
Mr Teerawat said several airlines use pay-to-fly schemes to cut costs, which can reach up to B6 million.
He said that if this unfair recruitment method becomes more widespread and remains unregulated, it could jeopardise industry safety standards.