For some background on the terminal, its Wikipedia entry is here.
It was an astonishing building when it opened in May of 1962, and remains so. TWA was staggering by the 1980s however, entering its first bankruptcy in 1991 and ten years later its remains were acquired by American Airlines. The terminal has had an equally uneven existence, and the plan is to transform it into a hotel -- the structure being the hotel's public areas (as best I can tell).
With one exception, the photos below were taken by me in June of 1965. They originally were slides that I scanned, cropped in many cases, and most had their color adjusted. They are not great photographic art, but might give you the flavor of the place when it was still fairly new.