I came across your web-page while searching for some information on Alfred Lowenstein. I have been interested in the mystery of his death for over 20 years and have done a bit of research on it. I think that Norris' theory of Lowenstein's own wife arranging his murder through the pilot is absolute garbage. Apart from the fact that Drew was not a murderous man, Mrs Lowenstein must have had plenty of other less risky ways of arranging her huband's "accidental" death, if she really wished to do so....which I seriously doubt. Despite his middle years, Lowenstein was a much more powerful man than Drew, and the chances are that a skirmish between them would more likely have resulted in Drew falling out rather than his employer! Also, maybe someone should have reminded Norris that "complete removal of the outer door" would have been noticed even before the plane took off.
Furthermore, consider the circumstances; Unless they were ALL in the plot (the secretaries included), someone would have remembered and mentioned the fact that Drew left the cockpit soon after Lowenstein. Or, do you want to believe that Hodgson and the dimunitive Baxter pushed him out when they pretended to be checking on him in the toilet, notwithstanding that there was no room for 3 people in the rear compartment? In any case, such an attempt would have caused enough disturbance to attract the attention of the secretaries, despite the noise of the plane.
I think it was an accident. Lowenstein must have been preocccupied during the flight, thinking about the blackmailer among other things. When he went to the toilet, he closed the door on the main cabin, not really registering this action mentally. This meant that while he was using the toilet, there was just the Aircraft door between himself and outside. After he was finished, he absent-mindedly assumed that he had shut the toilet door on himself (which he had not) and grabbed the airplane's outer door, which opened in the same direction. It probably resisted his efforts at first, but knowing Lowenstein's character, he could have easily driven his shoulder against it in impatience. The door opened a few inches and before he realised his mistake, he was sucked out by the slipstream.
You are wrong in your belief that the airplane's outer door could not be opened in flight . While it was true that doors on most similar Fokker Trimotors were very hard to open while in flight, later tests had clearly shown that this was NOT the case with Lowenstein's own aircraft. In fact, a man of average build could open that plane's outer door by as much as 18 inches while flying at a similar height as Lowenstein was at the time of the incident. Lowenstein was a powerful man.
I believe Norris' book should be classified in the same league as other publications that tell us that the Titanic did not sink at all or that Lindbergh accidentally killed his baby son and staged a kidnapping. Some people will do anything for a story.
Dr A. V.