What structural change would permit a worker to take initiative and say "Hey, these working conditions are wrong/inadequate and I will not safely do my job today unless proper changes are made", without risk of getting fired by higher-ups?

Empowering workers to make safety-critical meta-decisions does not seem to be a feature of actually-existing capitalism.

> What structural change would permit a worker to take initiative and say "Hey, these working conditions are wrong/inadequate and I will not safely do my job today unless proper changes are made", without risk of getting fired by higher-ups?

Well, what you are describing is a strike, and it is currently illegal for ATC to strike, so in theory one possible structural change would be to make it legal for the workers to do what you're describing.