This whole tale reminds me of the so-called "mystery" of the loss of Glenn Miller. Single engined aircraft takes off for a cross channel trip in bad weather and fails to make it - whatever could have happened? Must have been aliens or shot down by someone who was sick of his music!
Drunk airman goes stoogeing around "under the radar" (ie at low level) flying a large complex aircraft solo, and disappears. Has to have been shot down, what other explanation can there be? I can understand his widow clutching at straws, but not any of the other conspiracy theorists who always seem to reject the obvious explanation.