Indiana Jones

Lately, I've been reading Why Did It Have to Be Snakes? from Science to the Supernatural, the Many Mysteries of Indiana Jones by Lois H. Gresh and Robert Weinberg.  Recently, I read a section about zeppelins and how they relate to Indiana Jones and the Last Crusade.  The book claims that "after recovering the Grail diary in Berlin, the Joneses attempt to leave Germany aboard the majestic LZ 138 zeppelin," but when I referenced the film, I found that the ship's designation is actually D-138.  It's glimpsed in only a couple shots, though:

I hadn't noticed this detail before, but since it was drawn to my attention, I now think that it's slight reference to THX 1138, George Lucas's first feature film.  There are similar references in the Star Wars movies.  In A New Hope, Luke, in disguise as a stormtrooper, fabricates a "prisoner transfer from cell block 1138;" in The Empire Strikes Back, General Rieekan gives the order "Send Rogues 10 and 11 to Station 38;" and in The Phantom Menace and Revenge of the Sith, there are battle droids whose markings bear passing resemblances to the number.  (See more details here.)

When I re-watched Indiana Jones and the Kingdom of the Crystal Skull earlier this year, I noticed a 138 there, too.  It's one of the house numbers in the mock town that's destroyed by an atomic bomb test.