Chrissy Teigen, Patricia Arquette and more react to United Airlines leggings incident

"This disproportionately affects women," Arquette said of attire requirements.

Activist Shannon Watts first tweeted the incident early Sunday, writing, "A @united gate agent isn’t letting girls in leggings get on flight from Denver to Minneapolis because spandex is not allowed?"

Watts is a mother of five and the founder of Moms Demand Action for Gun Sense in America.

After major news outlets picked up reports of the incident in Denver, a spokesman for the airline confirmed the report to ABC News, adding that two teens weren't allowed on the flight because leggings are "not in compliance with dress code policy for company benefit travel," a program that lets the airline's workers and their families travel for free, but within certain guidelines. "There are different rules for these privileges because people are flying for free," the spokesperson added.

"This disproportionately affects women," Arquette wrote on Sunday. She also responded to another person's tweet, adding "Times change and discriminatory practices should be examined."

Teigen commented on past outfits she's worn for airplane travel and how she thinks those are far worse than leggings.

I understand. I suggest u consider updating ur rules 4 friends & fam as they seem to apply mostly 2 females & are outdated. https://t.co/41chqN32Q0

— Sarah Silverman (@SarahKSilverman) March 26, 2017

I understand. I suggest u consider updating ur rules 4 friends & fam as they seem to apply mostly 2 females & are outdated. https://t.co/41chqN32Q0