SEATTLE (AP) — American Airlines wants 47 Boeing 737s four years earlier than its original request, a move that industry experts said could signal a wave of orders for new passenger jets.American, based in Fort Worth, Texas, disclosed this week that it also had obtained purchase rights for the new Boeing 787, although it has not ordered any of that model.

Orders by the world’s largest airline likely herald a surge in orders for new planes from Boeing Co. and Airbus SAS from long-established “legacy” carriers, including several with aging fleets that have emerged from or remain in bankruptcy, analysts told the Seattle Post-Intelligencer.

“The US legacy carriers can’t put off for much longer ordering replacement planes, and that’s what we are starting to see,” Scott Hamilton of Seattle, an aviation industry consultant whose Leeham Co. Web site provides news, commentary and analysis on the Airbus-Boeing rivalry.

American’s announcement “supports our thesis that the current commercial aerospace cycle will be smoother than previous cycles as North America and Europe legacy airlines are just beginning to place orders for narrow- and widebody jets,” Ronald Epstein of Merrill Lynch wrote in a note to clients.

“We continue to expect more orders from these carriers in the next 12-18 months,” Epstein added.

In a deal announced yesterday, Boeing announced an order for another 787-9 from Low-Cost Aircraft Leasing, boosting that company’s announced orders for the plane to 15. The order previously had been listed for an unidentified customer on Boeing’s Web site.

Rising petroleum prices have hit especially hard at operators of less fuel-efficient planes.

American, which has not been through bankruptcy, decided to move faster to start replacing about 300 McDonnell Douglas MD-80s by having the 737s delivered in 2009-12, rather than in 2013-16 as previously ordered.

Airline officials said the fuel savings with 737-800s would be about 25 percent.