As of today, whether you're playing on an HTC Vive, Oculus Rift or PlayStation VR, you'll be able to join up with other eagles from around the world for multiplayer shenanigans. In the case of Eagle Flight that means more people to race against over the stylized, reclaimed-by-nature Parisian streets.
Ubisoft writes that Werewolves Within and the recently delayed Star Trek: Bridge Crew will support cross-platform play out of the box as well. There is one thing to note: Ubisoft is connecting the PS4 to PC players, something that's already been done with Street Fighter V. So, this groundwork has been laid out previously and (presumably) differs from connecting two closed online infrastructures like PlayStation Network and Xbox Live. Maybe that future is closer than we expect, though.