Yes, flight sims have always been the core base of support for TrackIR.

Mind you, it seems that's partly because TrackIR's manufacturers NaturalPoint had trouble attracting support from FPS developers. From the guy who was apparently product manager for NaturalPoint http://forum.il2sturmovik.com/topic/385-oculus-rift-headtrac... :

Thanks for the kind words. My larger point is that they have already won the battle, whereas NP and TrackIR only conquered one genre - flight-sim. OR doesn't really need the sim community, unless it completely flops with shooters. We make up less than 1% of gamers. I'm more sensitive to this stuff because I was in charge of TrackIR business development while I was at NP and I mainly left because I could not crack the shooter genre. It was really frustrating and I remember all these shooter devs and engine devs (including Gabe Newell when I showed him our mod for HL2 with head tracking)) laughing at me when I explained how cool TrackIR was and what it could do. They ALL told me it was a cheat and they would never take the time to implement special code to support a 3rd party device outside of a mouse and keyboard. Drives me nuts. What made them change their mind? The stupid screen? Weird.