A fun piece of trivia that builds on this is that the first episode to air, "The Man Trap", was neither the pilot with Captain Pike ("The Cage"), nor the second pilot with Kirk ("Where No Man Has Gone Before"). That second pilot became the third episode to air (on September 22nd), while "The Cage" was only available in full from the mid 1980s (1986 on VHS, 1988 on TV). Much of that episode did get released earlier, in the two-parter "The Menagerie" on November 17th/24th 1966, but as I say wasn't available in full for another 20 years.