She is introduced to their dress code by her boss

Isabel arrived at the airport excited, because working for a flight company meant that she was going to be able to visit many new places around the world just by doing a job. During her job interview she made a great impression, unknown to her mostly because of her looks. The interviewer told her that there were a few 'unorthodox' things she might had to get used to working for Air Netto, but didn't get into the specifics of it. Isabel didn't think much about that, and took the job no questions asked.

"Isabel, right? How nice to finally meet you!"

A tall, broad-shouldered woman with a deep voice greeted her upon arrival, hugging Isabel and motioning for her to come with her.

"Air Netto is so satisfied with having you on our team, and we sincerely hope you'll enjoy your job here with us", the brunette woman enthusiastically said. "I'm Michelle, and I'm your supervisor. I'm going to show you around!"

Isabel smiled and followed her. Michelle showed her the in and outs of the airport itself, as well as where the company's office was.

"And finally, our flight costumes!" Michelle said, with a hint of anticipation in her voice.

Isabel was puzzled.

What kind of costume did she see?