It is stated (and key to the plot) that Herdeg was the only survivor of the original experiment, but that is not true. Jimmy and several others of the ship's crew survived. In the original movie, Dr. Longstreet says that he interviewed the survivors.
The F117A had a range of 930 miles. Even if the Germans had launched it from the closest point in occupied France (over 3,000 air miles), it would run out of fuel and fall into the ocean about 1/3 of the way to Washington.
At around the 45min. mark, Mailer is listening to a western swing band as background to his video. The movements of the musicians (fiddle and guitar) do not match the music. A few minutes later, during his argument with Decker, the guitarist is still 'playing', but there is no sound.
In the alternate 1993 where the Nazis had conquered the U.S., no German was spoken by anyone including the soldiers and guards. It seems unlikely that The descendants of the Nazi's that occupied the U.S. would somehow switch to English. In addition to this, Mailer seems to be having trouble communicating in German when he meets his father in 1943. It's very unlikely the descendants of the occupying Nazis would abandon their home language and not force the surviving U.S. civilian population to learn German. No explanation for this is offered.