As AVSIM reported a month ago, there has been a license agreement put in place. Now Dovetail has confirmed that and stated; "The award-winning creators of the best-selling Train Simulator franchise have today announced a global licensing deal with Microsoft, granting them the rights to develop and publish all-new flight products based on Microsoft's genre-defining flight technology. The company is currently investigating new concepts in this area and is expecting to bring a release to market in 2015.
In addition to this licensing agreement, Dovetail Games is pleased to announce that it has also acquired the rights to distribute the multi-award winning Microsoft Flight Simulator X: Gold Edition via Valve's popular digital retail channel, Steam, entitled Microsoft Flight Simulator X: Steam Edition."
You can participate in the community discussion regarding this announcement here.