Indonesian carrier Lion Air is one of Boeing's biggest customers in Southeast Asia. Image source: Boeing.

China will buy 6,330 new commercial airplanes over the next 20 years. So says Boeing (BA 1.09%). And with Boeing currently controlling roughly 50% market share in China's commercial aircraft market, Boeing presumably wants to sell a lot of those airplanes to China.

But if Boeing is smart, it might want to lower its sights just a little and focus more efforts to the south.

And east.

Southeast Asia, to be precise.

Go Southeast, young man!
China's a great market to be in, no doubt. But with Boeing now neck-and-neck with Airbus (EADSY 0.58%) in the Chinese market, and at least two new homegrown Chinese airliners lining up to attack the domestic market as well, Boeing's share of the Chinese market is only likely to shrink over time. Meanwhile, Boeing itself has just identified a market that's nearly as big as the one in China, and arguably growing even faster than China.

Speaking at the Singapore Airshow earlier this week, Boeing senior VP for Asia Pacific and India Sales Dinesh Keskar predicted that Southeast Asia as a region will spend close to $550 billion buying 3,750 new airplanes of its own over the next two decades.

Most of these -- 76% -- will be single-aisle jets, such as Boeing's 737s and Airbus' A320 family of aircraft, which are perfectly sized to serve travel within the region. Passenger traffic in Southeast Asia, which as defined by Boeing includes such countries as Malaysia, Vietnam, and the Philippines, is likely to grow as fast as 7.7% annually over the next 20 years. According to previously published Boeing estimates, that's faster than the 6.6% pace expected out of China.

Who will win in Southeast Asia?
And yet, despite recognizing the opportunity in the region, Boeing seems to be struggling to capitalize on it. According to Boeing's order book, where the company keeps a running tally of backlogged orders by region, Boeing currently has 532 orders stacked up down there -- 86% of them for 737s. At the same time, Bloomberg reports that Airbus has orders for 463 aircraft outstanding at Lion Air alone (also a big Boeing customer) -- plus 430 orders at IndiGo and 307 more at AirAsia besides.

Tally up those Airbus orders, and it looks like Airbus is outselling Boeing by roughly 2 to 1 in this important market.

Lion Air also loves Airbus. Lots. Image source: Airbus.