Oh, a "strange plane". That explains everything </sarcasm>. Now, you intimate that the "strange plane" and the "NASA facility" are related, and I guess we're supposed to believe that the passengers were taken off the plane and herded into the "facility" for ultimate execution. Now, for inconvenient questions. Why do you think these passengers were all taken off the plane in full view of bystanders? They would have had to have been in order for your favorite conspiracist to have observed them. When these passengers "deplaned", were any of them acting in any way like they were being herded by men in black wearing sunglasses? Were any of them asking questions, maybe wondering why they weren't where they expected the plane to land? Was anyone frantically trying to contact loved ones, maybe making a break for it? If they were going to be killed anyway, why not just let them die in the crash? Much neater and simpler than risking exposure this way.
Why, if this was all so mysterious, are there no photos or videos taken of this "strange plane", if it was so strange that your favorite conspiracist made note of it?
See, this is where wild theories usually fall apart, when they get looked at below their shiny surfaces.