An unprecedented travel boom in Asia has spawned new budget carriers and millions of first-time fliers, but a shortage of pilots is threatening to choke demand.

Vietnam's Bamboo Airways Co., which launched this year, was the region's latest low-cost carrier to start services and more are expected to join the race. In Southeast Asia alone, LCCs have about 1,400 aircraft on order, compared with fewer than 400 for full-service carriers, according to CAPA Centre for Aviation. With the supply of pilots lagging behind, the airlines will struggle to find skilled cockpit crew.

"There's a real crunch coming," Peter Harbison, executive chairman of Sydney-based CAPA said in Singapore. "For new airlines, it's much, much harder and it's going to be a real struggle."