I trained with Frank Dux at his old Dojo in North Hollywood, California back in 1986-1988. All joking aside, the guy knows nothing about ninjutsu. He taught a hybrid art, which had a solid jujitsu foundation. But, it was not ninjutsu. He also had veteran army guys add what they learned in the military. So, from my experience and from what I heard and saw it was a fusion art. Frank Dux was a very eccentric character, but I don't believe for a minute he did all the things he claimed. I remember the black belt test was a week long. You had to dive out of a moving vehicle and I do remember you had to face multiple opponents in a wooded or desert setting. A guy I knew who took the test was taken to the Angeles Forest for the multiple attacker scenario. He told me how he had to use camouflage and stealth techniques as well. Testers were graded on all that stuff. It was very militaristic. I learned alot. More than most people learn in Dojos or Gyms today. What I learned saved my butt a few times. But, was it ninjutsu? honestly it was not. Frank Dux was trying to make money and who can blame him. We live in a capitalist and free market society. From what I have learned since then is that even Masaaki Hatsumi is considered a fraud in some circles. There are some Japanese who say his evidence of his lineage is shady and that the Iga and Koga Schools had died out long before his claims and that his teacher simply used the word ninjutsu without any evidence. Either way, Dux is no ninja but he is a martial artist.  
 his claim of having the fastest kick is insane. Bill Superfoot Wallace holds that title.