Thailand's domestic air traffic market has nearly reached saturation point, with very little room left for further expansion by airlines, according to the industry.
Executives of major budget airlines such as Thai AirAsia (TAA), Nok Air and Thai Lion Air (TLA) said that new routes are getting harder to find and ramping-up flight frequencies is almost impossible.
This comes as Thai skies have become overcrowded and main airports -- Suvarnabhumi, Don Mueang, Phuket and Chiang Mai -- are facing critical congestion, largely due to handling capacity constraints.
Meanwhile, competition has grown even more intense in recent years as airlines struggle to fill up seats, thus depressing yields and cutting into their profitability.
"Thailand's domestic market has almost reached saturation point," Santisuk Klongchaiya, commercial director at TAA, told the Bangkok Post.
The only place left for airlines to expand domestic service is through the introduction of inter-regional connections, such as linking U-tapao (Rayong) and Ubon Ratchathani, he said.
TLA chief executive Aswin Yangkirativorn agreed, saying this reality has prompted the airline to focus more on expanding abroad by introducing new international routes and raising frequencies on existing ones.
TLA is targeting regional expansion, particularly to China and India, to support its growth plan.
In the more immediate future, the low-cost carrier is eyeing opportunities to launch new services from its Bangkok's Don Mueang airport hub to Denpasar, the capital of Bali in Indonesia and Taipei, Taiwan, Mr Aswin said.
Adding Jiangsu and Kunming to its Chinese network is also on TLA's radar. That network currently covers Chengdu, Chongqing and Nanchang -- all from Don Mueang -- as the airline has seen travel demand from secondary cities in China surging.
At TAA, Mr Santisuk said the airline will press on with its strategic plan to increase coverage to Cambodia, Laos, Myanmar and Vietnam (CLMV), a region with strong economic growth potential, and focus less on domestic expansion.
TAA is set to launch a non-stop flight from Don Mueang to Danang, Vietnam on June 9.
The coastal city will become TAA's third port of call in Vietnam.
The carrier offers three flights a day from Don Mueang to Ho Chi Minh City and two daily services to Hanoi.
The new route will strengthen TAA's presence in CLMV, serving nine cities (including Danang) on 10 routes with a combined 21 flights a day.
In a related development, TAA yesterday confirmed that it will boost its Don Mueang-Phnom Penh route to three flights a day on May 19 from two daily at present.
TLA is on course to add five more B737 aircraft this year, bringing its total fleet size to 30 by year-end.
TAA is also committed to raising its fleet of A320 jets to 57 by the end of this year.