Well they already said it will be on Xbox One? What do you mean by "next gen"?
Where did they say XBox One?
XBox consoles and earliest release date is 2020 for windows 10. By the time it comes to any XBox consoles the next gen consoles are out, so likely it's a next gen XBox console title. But perhaps there will be a streaming version which you can stream to XBox One etc. Latency won't be much of a problem with a flight sim. It might actually be better to stream the game as downloading the data to render locally will take a lot more bandwidth.
I wonder if I get to crash a 747 into my own house, err I mean land a water plane on the river next to my house :)