Updated below: After an extended and bitter absence, American Airlines is once again allowing third-party mileage-tracking sites to get access to its AAdvantage program information for their site users.

American Airlines and AwardWallet announced today that AAdvantage would once again be available to AwardWallet, and its members and customers, after the airline cut off the loyalty-tracking site in December 2011.

Asked what led to the breakthrough, Cory Garner, American Airlines’ managing director of sales operations and distribution, tells Skift: “AwardWallet provides a valuable service, and they have given American comfort that the data which they will access will be handled in a way that is consistent with the expectations of American and its customers.”

The return of AAdvantage to AwardWallet after American cited security and intellectual property concerns means that other third-party tracking sites that access AwardWallet’s API can once again provide updates to their members about their AAdvantage accounts. In the past, companies and apps such as TripIt Pro, Traxo, UsingMiles, MileWise (acquired by Yahoo and shut down), and Superfly have accessed AAdvantage through AwardWallet.

UPDATE: Not so fast, Garner says. Tracking sites such as TripIt, Traxo, UsingMiles and Superfly would each have to sign their own agreements with American Airlines before they would be allowed to show AAdvantage account updates to members even if they use the AwardWallet API.

These third-party tracking sites enable frequent flyers to track all of their points and miles in one dashboard instead of having to track each separately, AwardWallet, for example, track close to 700 airline, hotel, car rental and credit card loyalty programs.

AwardWallet CEO Alexi Vereschaga said he’s unsure what led to the deal, although he’s excited about it.

“Technically everything is still the same and we are still parsing their site,” Vereschaga said. “But they are preparing an API for us, so it will probably change going forward.”

“I am not 100% sure what changed their mind, perhaps it was the pressure from the frequent flyers,” he adds. “We never talked about it, they just said they want to do it. They evaluated us in terms of security and placed some contractual obligations, and we made it happen. I am pretty excited.”

Despite the return of AAdvantage to AwardWallet, Delta and United, both of which dropped out late last year, remain absent, and Southwest only lets one third-party site, Points.com, track its loyalty program for users because of a commercial relationship.