Now, the Houston-based company says it is “vigorously defending itself against all such allegations,” in a press release posted on its website. TapJets claims the flights in question were conducted during the “initial development of our company,” and that the passengers on those flights were non-paying friends and family members conducted to test software. As such, the flights would be classified under FAR Part 91.501, not Part 135, which would be the federal regulations the FAA alleges the company violated.