It's amazing that after all these years, we're still learning more about the production process of the original Star Wars films.
One big revelation on the most recent Blu-ray release is that there were originally four women in the strike force that helped Luke attack the second Death Star. The Blu-rays have been out for a while, but there is so much material to mine out in there is always more to find.
In the special features, there are photographs and some deleted scenes depicting these actresses in costume and on set. Apparently the scenes were written, filmed, and even shown to test audiences, then cut from the film before the final release. Two of them, a pair of A-Wing pilots are shown in a pair of clips in which they are flying the craft looking into the camera, same as the other pilot shots.
Both of these pilots' facial footage ended up on the cutting room floor. One had all her lines replaced with a single spoken-only line in a masculine voice - before being exploded by a TIE Fighter. The other is simply completely absent.
We know even less about the two female X-Wing pilots. We have no footage from either, and a photograph of only one.
We do know this actresses' name, however, it's Vivienne Chandler. She's played bit parts here and there in Hollywood since the early 70's, but nothing you'd likely recognize ( for example, she was part of a dream sequence in Clockwork Orange, and later played the part of Sherlock Holmes mom in Young Sherlock Holmes).
She apparently wasn't intended as a background character, either. Her character had nearly a minute of dialogue interacting with Luke before being blasted out of space. Who can say where her acting career may have gone had she remained a part of that scene.
It's only speculation why these actors were cut from the final print, but they were the only pilots cut, and they were the only female pilots, so it stands to reason that they were removed simply because they were female. Also, since they were cut between the test-audiences and the final release, it was likely because of the test-audiences' response. Thus, the prevailing theory is that people didn't like seeing women blowing up on screen.
The only good way to see more about these lady pilots is to grab the most recent Star Wars Blu-ray box-set which was released late last year.