I'm an FA for Southwest Airlines. We have some of the ugliest uniforms in the industry. For years, though, it was in our contract that our uniforms were to be made of only natural fibers. Some how, that section went missing in our new contract and the 100% cotton uniform is slowly being replaced with a polyester/cotton blend.
Why? Cost of replacing cotton which wears out faster and fades from washing. But, we're still allowed to wear tennis shoes on the job. We look like idiots, but I'd rather evacuate in sneakers than heels.