I didn't even realise X-Plane 11 [official site] was in-development, though of course it is. The flight simulator series is the only real competitor to Microsoft Flight Simulator, with its own approach to physics modelling, and X-Plane 10 was my pick when I wanted to take a skyward jaunt. The new game is due before the end of the year and now there's a demo out that you can download now and a trailer showing some of the features below.
Where other flight simulators model plane physics using available aerodynamic data for each featured plane, X-Plane simulates flight from first principles. That is, it calculates the forces of lift and drag against the actual polygonal shape of the plane you're attempting to fly. This means the game theoretically produces a more accurate flight experience, but also that you can include planes for which no aerodynamic data yet exists. Technically you could use X-Plane to design an entirely new plane and test how it might perform in the real world based on its performance in-game.
As an amateurish amateur in the world of flight simulators though, this is not where my interests lie. My interest is in using the game as a kind of tourism, since it includes the entire planet, much of it in great detail, and when else am I going to be able to buzz above the alps from that kind of height. Or failing that, my interest is in using the game's simulation to create dramatic emergency landings, by setting a percentage chance for my plane to fail within a certain timeframe, turning the weather to stormy, and seeing whether I can navigate myself to a runway and touch down safely when everything suddenly goes wrong.
For that reason, I'm not sure I'll notice most of the new additions X-Plane 11 is bragging about, including more detailed plane models. I do like the sound of the new user interface however, which seems to like it will make creating my own disaster scenarios a little easier. There are videos detailing some of these changes on the game's YouTube channel.
X-Plane 11 is due for release this year and is currently available in beta. You can buy the game for $60 direct from the developer, which currently also gets you access to a digital download of X-Plane 10.