American Airlines plans to launch an international premium economy product later this year — the first of its type on any U.S. carrier — and while American brings its booking systems up to speed, the cabin will be free for elite customers.

The service is planned for American’s new Boeing 787-900 Dreamliner aircraft, which is slated for delivery later this year. Multiple publications reported last week that the two initial routes for that aircraft will be from Dallas to Madrid, Spain and Sao Paulo, Brazil.

Digging deeper, however, the blog View from the Wing pointed out that the mechanism for booking and upgrading through Premium Economy won’t be available until some point in 2017. As a result, between the launch of the 787-900 and implementation of the Premium Economy booking process, the cabin will be treated like Main Cabin Extra, which currently operates simply as an extension of the standard economy cabin. This means that elite passengers, who are normally given access to Main Cabin Extra for free, will be given free access to Premium Economy. It should also be possible for non-elite passengers to purchase “Main Cabin Extra” and effectively get an upgrade into Premium Economy.

American’s international premium economy product, which is an entirely new class of service (versus Main Cabin Extra, which is effectively economy with more leg room), will feature wider, more comfortable seats than traditional economy plus a broader range of perks like meals and amenity kits. The cabin will initially go into service on 787-900-operated flights but will eventually roll into other international cabins as well.

American still hasn’t given full details into how its Premium Economy product will eventually be priced or managed in terms of elite or mileage-based upgrades, so this narrow window may be one of the only opportunities for ultra-budget travelers keen on buying the least expensive ticket to try out the product. Once American’s IT system catches up with its aircraft, getting free or cheap extra leg room on international flights is going to get a whole lot harder.

Photo Credit: A promotional image of American Airlines' new international premium economy seats. American Airlines