Also -- the up-front rules on the first page make no mention of production quantities, only that the aircraft must have "entered service".  I interpret that to mean deliveries were accepted by the armed services.  That usually means the aircraft was flown by military pilots, not just civilian test pilots.  So, no lower limit on production.  If we limit it to "thousands produced" it makes it even harder to come up with the right kind of clues (not too easy, not too difficult).  It also severely limits the playing field.  I hope everyone agrees that this is more fun when the answer is not immediately at hand :-)

So gentlemen, here are your next clues...

Gary