Earlier this year, Airbus (OTC:EADSY) bit the bullet and announced that it would wind down production of its slow-selling A380 jumbo jet by 2021. With the exception of Emirates, the A380 failed to win any big fans, and a multiyear order drought ultimately forced Airbus' hand.

Since that decision was announced back in February, the Airbus A380's popularity has waned even further. A growing number of airlines that operate the jumbo jet have announced plans to retire their A380 fleets prematurely in favor of more efficient jets. That's great news for Boeing (NYSE:BA), which may be able to sell more 777-9 jets over the next few years as airlines plan for the replacement of their A380s.

The retirement announcements just keep coming

Around the time Airbus announced its decision to stop building new A380s, Qatar Airways revealed that it plans to retire each of its A380s as they reach 10 years of age. This would put the retirement dates for its 10 A380s between 2024 and 2028.

A typical commercial jet has a useful life of 20 to 30 years. However, retiring A380s after just 10 years wouldn't be unprecedented: Singapore Airlines -- the second-biggest A380 customer in the world -- has already retired five of its A380s at the 10-year mark. At least two of those planes are in the midst of being scrapped.

A Singapore Airlines A380

Singapore Airlines has already retired its oldest Airbus A380 jumbo jets. Image source: Singapore Airlines.

A month later, Airbus agreed to buy back six of Lufthansa's 14 A380s in conjunction with the latter's order for 20 additional A350-900s. Given the lack of a secondary market for the A380, these planes are likely to be scrapped, too. Returning the A380s to Airbus will clear the way for Lufthansa to take delivery of the 20 777-9 jets it has ordered from Boeing.

Even Emirates -- which hasn't finished taking delivery of all of the A380s it has ordered -- has already started talking about when they will disappear from its fleet. A couple of months ago, company president Tim Clark stated that Emirates would continue flying A380s until the mid-2030s. Of course, that's just the end date for the carrier's A380 retirement process: The oldest ones could potentially begin leaving the fleet just a few years from now.

Most recently, Air France revealed last week that it will retire all of its Airbus A380s by 2022. Even its oldest A380 would be just 13 years of age by then.

Retirements can be contagious

With so many airlines starting to retire Airbus A380s at such a young age, the active global fleet of A380s will start declining pretty soon. Over the next five years, the changes will probably be fairly minor. But in the five years thereafter, the number of A380s still in service could drop precipitously, particularly if Emirates sticks to its typical schedule of keeping planes for no more than 10 to 15 years.

An Emirates A380 jet

Image source: Emirates.

As the active fleet shrinks, it will be harder to maintain a network of spare parts throughout the world. Additionally, engine maintenance could become prohibitively expensive, due to the lack of scale. (Aside from the A380's low sales numbers, it also had two engine options.)

This will make it challenging for airlines to keep the remaining A380s in the air. In effect, the decision by many airlines to retire their A380s at a very young age could force other airlines to follow suit by making the jumbo jets even more expensive to operate than they already are.

Can Boeing cash in on this opportunity?

After A380 deliveries end in 2021, the Boeing 777-9 will be the largest commercial jet still in production. It will also be the most efficient commercial jet in the world, according to Boeing. That makes it a natural A380 replacement -- although some airlines are opting for the somewhat smaller Airbus A350-1000 instead, either for fleet commonality reasons or because they have decided that smaller jets work better for their route networks.

A majority of the top A380 operators have already ordered 777-9s. However, most of those orders were primarily designed to replace other aircraft models or for growth. That leaves plenty of room for follow-on orders in the coming years. Boeing's backlog contains 344 orders for 777X jets today -- nearly all 777-9s -- so getting another 100 or 150 A380 replacement orders would give the program a nice lift.

The biggest risk to getting those orders would have been if airlines chose to keep operating their Airbus A380s well into the 2030s. By that point, a better replacement might be available.

It doesn't look like that will be an issue, though. The vast majority of the global A380 fleet is on track for retirement over the next decade or so. There isn't likely to be a good alternative to the Boeing 777-9 within that timeframe. Thus, Boeing can look forward to more 777-9 orders rolling in as airlines finalize their A380 replacement plans in the coming years.