Star Wars (1977) originally had Red and Blue Squadron attacking the Death Star, but blue conflicted with the blue screens, so it was changed to gold. In Rogue One (2016), Red, Gold and Blue squadron attack Scarif, where Blue Squadron is destroyed, leaving them unavailable for the events in Star Wars

Image from preview.redd.it and submitted by MovieUnderTheSurface
image showing Star Wars (1977) originally had Red and Blue Squadron attacking the Death Star, but blue conflicted with the blue screens, so it was changed to gold. In Rogue One (2016), Red, Gold and Blue squadron attack Scarif, where Blue Squadron is destroyed, leaving them unavailable for the events in Star Wars

Tattoomyvagina on September 12nd, 2020 at 20:35 UTC »

I love how the Blue Leader has a 1970s period mustache so it looks like he would fit right into the other styles at the time too

Khclarkson on September 12nd, 2020 at 20:37 UTC »

You also see Red 5 going down while trying to open the shields. This later becomes Luke's call sign when he joins Red Squadron to attack the Death Star in episode IV

nikhkin on September 12nd, 2020 at 20:53 UTC »

They also used some of the unused footage of Gold Leader from the original Star Wars, along with a handful of new lines of dialogue.

https://www.radiotimes.com/news/2017-01-06/original-star-wars-actor-reveals-how-his-character-was-brought-back-for-rogue-one/