Thanks, appreciate it! For anyone else wondering, two separate products:
FlyInside Flight Simulator - A completely stand-alone flight simulator, built for VR. No relation to FSX, and doesn't use your FSX aircraft. It comes with 10 high-quality aircraft built by Milviz and TFDI
FlyInside FSX - Adds virtual reality support to Microsoft Flight Simulator X. Doesn't come with any aircraft of its own, but you can use (nearly) all of the aircraft you have in your FSX installation