SINGAPORE -- Singapore's efforts to claim the status of Southeast Asia's airport hub is complicating an airspace dispute with Malaysia, as the city-state's strategy to ramp up airport capacity has sparked a major backlash from Kuala Lumpur.

At stake in the dispute is Singapore's plan to modernize the airspace management of Seletar Airport, its little-known second airport, in order to handle more flights. Kuala Lumpur has claimed that the project would hamper plans for tall buildings in southern Johor, a Malaysian state on the other side of a narrow body of water separating the two countries, over which some Seletar flights travel.

As the regional battle to be Southeast Asia's main airport hub intensifies, Singapore has been ramping up Seletar's capacity in order to make full use of its main Changi Airport. Seletar, located in the north of the city near the Malaysian border, is mainly used for private flights, medical evacuations and maintenance, with some 30 aerospace companies including Bombardier and Rolls-Royce having maintenance and repair operations there. Seletar is managed by Changi Airport Group, the main airport's operating company.

Bulking up Seletar's capacity would mean Singapore could shift turboprop aircraft operations -- which usually carry fewer passengers than jets -- from Changi to Seletar. The shift "will help to free up capacity for jet aircraft operations at Changi Airport," according to the operating company, thus making more efficient use of Changi as regional competition increases.

Southeast Asia's rapid economic growth has led to a sharp rise in the number of air travelers. In order to catch up with growing passenger demand, other major airports in the region, including in Bangkok and Jakarta, are also rushing to expand capacity. Singapore's Changi Airport plans to add a fifth terminal by 2030 and a third runway in the early 2020s.

But until the expansion projects are completed, Changi must get by with its existing facilities -- a situation that has led the city-state to look to Seletar as a solution.

In 2011, Seletar extended its runway by 250 meters to support bigger planes. In November this year, its terminal was renewed with expanded capacity of 700,000 passengers per year -- a big change given that the old terminal handled 26,700 passengers in 2015.

Seletar also plans to introduce the Instrument Landing System, a precision runway approach system that was developed to enable planes to land safely even in poor visibility. Aircraft currently rely on pilots' eyesight to land safely.

But the ILS plan has caused Malaysia to intervene. The Malaysian government said on Dec.4 that the new landing system, which requires a safety buffer on the flight path, would affect construction activities in its territory. However, if the ILS is not in use, Kuala Lumpur claims that pilots would be able to maneuver around obstacles, such as tall buildings.

Kuala Lumpur also raised another issue. Malaysian Transport Minister Anthony Loke said his country wanted to regain control of airspace over southern Johor. Based on a bilateral agreement between the two neighbors, Singapore has provided the area's air traffic control services since 1974.

Singapore's national flag, left, raised in front of the Seletar Airport terminal. (Photo by Kentaro Iwamoto)

Singapore has not taken kindly to what it sees as bullying by Malaysia. "I think the situation seems to be using this technical excuse to trigger demand, to change the airspace arrangement which was brokered by International Civil Aviation Organization long, long ago, which has worked very well, benefiting all stakeholders in this region," Singapore's Transport Minister Khaw Boon Wan said on Dec. 12.

For Singapore, maintaining control of the southern Johor airspace is an important part of its strategy to be the region's main airport hub and have efficient air traffic control. Shukor Yusof, head of aviation research company Endau Analytics, told the Nikkei Asian Review that thanks to the current airspace arrangement, "More aircraft fly into Singapore than they do to [Johor's] Senai Airport, the closest international airport."

Loke in early December said Malaysia was capable of managing the southern Johor airspace as the country had improved its air management skills. However, Shukor pointed out that "Malaysia's track record in air traffic control leaves a lot of room for improvement," citing the disappearance incidence of Malaysia Airlines' flight MH370 in 2014.

Singapore and Malaysia are expected to have a bilateral meeting in early January, during which the issue will be discussed.

As far as the technical issues at Seletar's new landing path is concerned, Singapore's Khaw on Dec. 12 said that, "With goodwill, I am confident a mutually satisfactory technical solution can be found." Malaysia's Loke on Dec. 13 said, "On any technical considerations, I think I will leave it to the technical experts from both sides to thrash it out."