The 80-minute flight between Jakarta and Singapore has become the world's fastest growing international route since Indonesia and Singapore inked a deal to expand air links in January.
"The almost 130,000 return seats make Singapore-Jakarta the second largest international route in the world.
No other route in the top 10 has seen growth above 20 per cent," the Centre for Aviation (Capa) noted last week.
It estimates that the number of one-way seats on some 298 flights between the two capital cities will reach 65,000 a week in November, up 24 per cent over the same period last year.
Singapore Airlines operates the most number of daily flights to Jakarta - nine - compared with other SIA destinations.
National carrier Garuda Indonesia has also added a ninth daily flight and is using a bigger plane for at least four of the flights.
This upsizing will see a 46 per cent increase in the number of seats in November, compared with the same period last year.
Tigerair Mandala saw a 14 per cent rise in market share of the route after adding five more daily flights for a total of seven.
The increased air links have put pressure on Jakarta to expand its airport - already running over capacity - to meet demand.
Indonesia's robust economic growth in recent years has led to a burgeoning middle class and rising affluence which, in turn, has seen increased travel demand by the country's 240 million people.
Though work to expand Jakarta's Soekarno-Hatta airport began last year, officials admit the expansion will not be able to cope with the rising number of passengers.
State-owned Enterprises Minister Dahlan Iskan described the airport's overcapacity as severe.
"We have had to reject 170 international flights from landing here so far this year because there are simply no more slots to land," the minister told reporters last month.
Flight delays are common these days, and the strain has resulted in blackouts and telecommunication disruptions.
The Transport Ministry is looking into land reclamation off Jakarta's coast to build a third runway.
Ministry spokesman Bambang Ervan has also urged carriers to operate more direct flights from west to east Indonesia, which will take some of the load off Jakarta.
There are no direct flights to Europe from Jakarta.
Boutique owner Welda Sari, who travels to Europe four times a year to source for goods, flies to Singapore for connecting flights. "The airport is cleaner, more efficient and has more connections."
"Changi in many ways is the main international hub for Indonesia and if Indonesia's airports don't expand, they will continue to lose potential passengers to Singapore," said Capa's chief analyst Brendan Sobie.
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