Luke was introduced as a pilot of land and maybe airspeeders, not starships. Where did he get training for starships? He never attended the academy. And the Lars didn’t look to have any starships.
It doesn't matter where.
"Han Solo: But who's gonna fly it, kid? You?
Luke Skywalker: You bet I could! I'm not such a bad pilot myself."
establishes that he could fly a starship. That he was going to head to the academy, that he mentioned Beggars Canyon...that he was a pilot was "built into" the character. We don't ask where Han Solo learned to fly either - we just accept that he did because it is in his character.
Rey was introduced (admittedly not in the movie, but in the young adult book released prior to the movie
If it isn't in the movie - it didn't happen. There is a major difference between unanswered questions, and plot holes.
Rey was introduced in the movie as a scavenger and there was absolutely zero indication that she had any flight training, formal or informal. Her ability to fly was fairly central to the start of the movie but her character description, as shown, gave us a character who should not have been able to fly. This is one area where TFA was bad - what shoudl ahve been left at the level of unanswered questions to be explored later became fairly important to the plot of TFA with a necessity to be somehow addressed. Reys ability with the Force for example - she should have been shown using it. Not very well, but enough to show that she had gained some knowledge of it. That she was talented, but untrained. The boy at the end of TLJ, grabbing the broom - that should have been Rey at the start of TFA.
Reys introduction as a pilot was another of those moments. Since she wasn't introduced as a pilot, we needed something to explain away her skill and proficiency. Even - as with Luke in ANH - a simple sentence or two. That explanation never occurred.
So yeah - I'm with those who state that elements central to the story shouldn't be divided between mediums. A Mechanic telling Rey that the sims were offline or similar would have been enough. Not perfect...Rey didn't want to leave Jakku so why was she engaged in sims? Better if she had wanted to leave to go search for her parents.
And those "hiccups" had her fly a large ship through a Star Destroyer while more nimble, smaller TIE fighters with trained and experienced crew crashed.
So - no. That an explanation was in a book doesn't mean much.
