Some special effects really on very simple camera tricks and no post production techniques whatsoever.
Two Eyes Are Better Than One Lying Camera Eye
"Forced perspective is a technique which employs optical illusion to make an object appear farther away, closer, larger or smaller than it actually is. It manipulates human visual perception through the use of scaled objects and the correlation between them and the vantage point of the spectator or camera. It has applications in photography, filmmaking and architecture."
Low Budget Visual Effects - Forced Perspective
Launch of Atlas V Rocket with Cygnus OA-7 Cargo Craft
NASA rocket launches look like hot air balloons slowly rising into the sky. How very interesting.
Highly edited footage is proof of nothing. It seems likely any reports of anyone seeing such slow rising NASA (and other space program) rocketry are either word of mouth fantasy or the accounts of people who had (perhaps) witnessed a hot air balloon based visual hoax.
I tend to think the edited footage of the crowds are as contrived as the rest of it all and the people we see in the footage seemingly watching the rocket launches are in actuality looking at nothing but empty blue sky.
Some of the clips of the rocketry looks like fake rocket imagery that was composited over real footage. This is something that is easily done today with modern computer software, but was always a darkroom film technique.
This explains the visual magic trick.
Movie Magic Episode 5 - Forced Perspective Discovery Channel