20 Things You Didn't Know About Star Wars: Rogue One
5. Blue Squadron Was Originally Intended To Appear In A New Hope
In addition to the Red and Gold Squadrons, the Battle of Scarif also featured the new Blue Squadron, which curiously enough was actually intended to show up in A New Hope's final battle.
However, the blue colouring of the spacecrafts caused technical issues with the cutting edge blue screen technology being used during A New Hope's effects-heavy sequences, and so the colour was changed to red.
But four decades on, compositing technology had evolved enough that this wasn't a problem, and so Blue Squadron could be easily reintegrated.
And by having the entire squadron go down during the Battle of Scarif, there's a plausible reason for their lack of presence in A New Hope and beyond.