Tomorrowland was still largely unfinished when the park opened in 1955, and the Astro Jets did not debut until March of 1956. With its bold red and white checked pattern, it looked like a giant toy. The cyclops headlights are a nice touch, I'm sure it was quite a sight after dark! The Monorail and Submarine Voyage are just visible, they both opened only a few months before this photo was taken.
The jets were removed in 1966, I wonder if they were relocated to another amusement park, or if they went to the scrap heap. I'd love to have one of the rockets!