Artist rendering of the 737 MAX 8. Photo: Boeing.  

Up until 15 years ago, Boeing (NYSE:BA) was the undisputed top dog of commercial airline sales. Now, however, European Aeronautical Defense and Space's (NASDAQOTH:EADSY) Airbus is nipping on Boeing's tail, and while Boeing still maintains a bigger, active global fleet, Airbus is closing the gap. Further, in Latin America -- one of the fastest-growing commercial airline markets -- Airbus has outsold Boeing in five of the past six years. More importantly, in 2014, Airbus said it expects its market share to eclipse Boeing's. Here's what else you need to know. 

Airbus takes aim
In 2000, Airbus' commercial airline market share in Latin America was a paltry 12%. However, in 2014, Airbus expects its fleet to make up 52% -- and it expects its market share to continue to climb. According to Reuters, Rafael Alonso, executive vice-president for Airbus in Latin America, said: "We expect our market share should continue to increase in the coming years. A major achievement for us will be getting to 60 percent."

The VivaAerobus Group has signed a purchase agreement for 52 Airbus A320 Family aircraft (40 A320neo and 12 A320ceo), representing the biggest Airbus aircraft order by a single airline in Latin American history. Photo: Airbus.

More importantly, according to Airbus' latest Global Market Forecast, Latin American airlines will require 2,307 new aircraft between 2013 and 2032, which is estimated to be worth $292 billion. That's fantastic news for Airbus.

Boeing bites back
With Airbus outselling Boeing in Latin America in five of the past six years, it's easy to believe that Airbus will dominate that market. However, Boeing isn't going down without a fight. Donna Hrinak, Boeing's most senior executive in Brazil, said that one of the major factors behind Airbus outselling Boeing is the Airbus A320 neo, which had a launch date of December 2010. Hrinak said, "They came out first with their 'neo', which gave them a headstart on sales." By contrast, Boeing's 737 Max had a launch date of July 2011, so it's had to play catch-up.  

Further, Hrinak said that Boeing will continue to keep things competitive in Latin America, and with Boeing estimating that Latin America's fleet will almost triple by 2032 to 3,790 planes, there's no doubt that Boeing will live up to this promise. 

What to watch
Boeing is a massive company that gets a significant amount of its revenue from commercial airline sales. In addition, as of its third-quarter report, Boeing's backlog was $415 billion. But, as I previously wrote, Boeing has received a few blows when it comes to commercial airline sales -- arguably the most notable being the loss of Japan Airlines to Airbus. What this means is that while Boeing has a significant safety net, there's reason for investors to keep a close eye on Boeing. Airbus is continuing to show that it's a major contender when it comes to commercial airline sales, and Boeing might have to step up its game if it wants to continue being the top dog.

Further, the fight for Latin America is one that investors should especially keep a close eye on. Latin America is one of the fastest growing aviation markets, and if Airbus continues to eat away at Boeing's market share, that's a bad sign for investors. That's not to say it's time to bail on Boeing's stock, but it would be a good idea to continue watching Airbus' performance.

Fool contributor Katie Spence has no position in any stocks mentioned. Follow her on Twitter: @TMFKSpenceThe Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.