The Renton-built, Next Generation 737 is part of what’s being billed as the largest airplane order in aviation history.

American Airlines announced Wednesday an order for 460 single-aisle aircraft from Boeing and the European airplane manufacturer, Airbus. Boeing’s share is 200 737s, with options for an additional 100 airplanes.

The Associated Press is reporting the total order is worth about $38 billion at list prices.

American Airlines has an aging fleet that today includes no Airbus airplanes.

The order is significant for Renton because it includes 100 737s equipped  with a new, more fuel-efficient engine, with options for 60 more. Until now, Boeing has only talked about the possibility of developing a new engine as a possible alternative or initial step to building a replacement for the 737.

It wouldn’t take a new plant to install a new engine on a new member of the 737 family. But there’s no guarantee that a 737 replacement would be built in Renton.

Mayor Denis Law said in a statement Wednesday the City of Renton “is extremely pleased that The Boeing Company has chosen to extend the life of the world’s best-selling commercial aircraft, by introducing a new variation with more efficient engines.”

The new engine for the 737, he said, “offers greater assurance that for many years to come thousands of workers will remain on the job in Washington State and right here in Renton, the best place in the world to produce commercial airplanes.”

American Airlines will take delivery of 100 737 Next Generation airplanes starting in 2013; it has options for 40 more. The 737s with the new engine would come later; Boeing’s Board of Directors has yet to approve its development.

“American is pleased to be the first airline to commit to Boeing’s new 737 family offering, which is expected to provide a new level of economic efficiency and operational performance, pending final confirmation of the program by Boeing,” according to an American Airlines news release.

Jim Albaugh, CEO and president of Renton-based Boeing Commercial Airplanes, in a new release called “American Airlines is an industry leader whose vision and disciplined approach to growth has made it one of the largest airlines in the world.

“This agreement will provide American Airlines with the most capable airplanes in the narrow-body marketplace and continue to deliver industry leading economics. Demand for the 737 remains very strong from customers around the world and we have deliberately retained delivery positions to meet the fleet requirements for all our valued customers.”

Boeing has a backlog of about 2,000 orders. About 5,700 737s have been ordered.

American Airlines’ current fleet of more than 600 Boeing airplanes includes 156 Next-Generation 737-800s, according to a Boeing press release.

The agreement builds on American Airlines’ existing backlog of 64 Boeing airplanes consisting of 51 737-800s, seven 777-200ERs and six 777-300ERs, according to Boeing. In addition, American Airlines has an existing purchase agreement with Boeing to acquire an initial 42 787-9 Dreamliners, with the right to purchase up to 58 additional 787s.

The other half of the American order includes American 260 Airbus aircraft from the A320 family and will have 365 options and purchase rights for additional aircraft, according to an American press release.

American will take delivery of 130 current-generation Airbus aircraft beginning in 2013. Beginning in 2017 American will begin taking delivery of 130 aircraft from the A320neo (New Engine Option) Family featuring next-generation engine technology. American is the first U.S. airline to use this new-technology aircraft.

In a statement Tom Wroblewski, the president of Machinists Union District Lodge 751, called the announcement “good news for everyone: residents of Washington, the Boeing Co. and its workers, and especially, American Airlines and its customers.

“With the re-engined 737 – assuming Boeing’s board approves the plans – American Airlines will get the best of both worlds. It will get an improved version of the 737 that already was the market leader in its class. And at the same time, it will get a plane that will be built by our industry-leading workers in Renton, who prove to the world every single day that they can be relied on to deliver airplanes on schedule.”

The order for the new engines, he said, “gives us a sense that Boeing recognizes the value of its greatest asset, that being its skilled workforce here.”

Law pointed out that Boeing has produced airplanes in Renton for more than 70 years.

“The City of Renton is demonstrating on a daily basis our commitment to meeting Boeing’s needs,” he said. “Last year we signed a new long-term lease agreement with Boeing for its use of Renton Municipal Airport and we continue to ensure a seamless and speedy permitting process for the capital improvements to the Renton Plant as the company ramps up its production capabilities.  We certainly stand ready to accommodate any new requirements that today’s decision will bring about.”