Continuity mistake: When Thunderbird 1 prepares for take-off, it moves down a ramp and the launch site is seen at the end. It then cuts to a shot of it moving down the ramp, and then of it arriving at the site. The Thunderbird has suddenly rotated 90 degrees between shots.
Continuity mistake: When Thunderbird 3 takes off from Tracy Island, look at the "3" at the bottom of the rocket when it goes up from the hangar. It is a completely different "3" to the one that was seen in the previous shot.