&gt; Other commercial flying objects are rigorously safety tested for their ability to remain in the air despite different mechanical failures.<p>The key phrase here is <i>commercial</i>. There are strict regulations on commercial aircraft, but there are no such requirements for home-built or kit built aircraft. (quick edit, there are regulations&#x2F;requirements for all aircraft, but it&#x27;s a much lower standard for home-builts than for commercial)<p>Many people think that there aren&#x27;t many kit aircraft out there, but there&#x27;s actually a huge number. Oshkosh is the largest airshow in the U.S. for experimental aircraft and there were over 10,000 experimental aircraft at the show last year. There&#x27;s even more who didn&#x27;t attend the show! For comparison, Delta Airlines operates about 800 aircraft.