Jessica Chastain Is Calling Out Airlines for How They Pay Flight Attendants (Video)

Academy Award Nominee Jessica Chastain is taking up an unlikely cause.

For those who are unaware: it is standard practice among airlines to only begin counting flight attendants' hours from the moment the cabin doors close. They are financially "off the clock" the moment the flight pulls up to the destination gate, though every airline has their own specific set of rules.

On Monday, Chastain tweeted that she "just discovered that flight attendants don't get paid during boarding or delays." She tagged a few airlines in the tweet, asking how it could possibly be legal.

American Airlines responded to the tweet, saying, "Contracts are negotiated between the company and the unions to determine the details of any compensation package." But Chastain pushed back by asking, "How could it be legal to not pay your employees while they are serving your customers and performing safety related duties?"

The answer goes back to the Railway Labor Act. The act, which was passed in 1926 and last amended in 1936 to include airlines, outlined the rules for an elaborate bargaining process between management and labor unions. "It also prohibits the unions or management from making any changes in the status quo without a release by the board," according to a 1988 New York Times article.

Basically, because of this rule, unions representing flight attendants have a very difficult time negotiating changes. "Airlines are adamant about not ever changing this method of calculating time for pay purposes," one pilot and union negotiator wrote on Quora.

"They pay us per diem, which is less than $2 from sign in - the time we get back to base," flight attendant and author Heather Poole responded on Twitter. "Our pay rate sounds really great until you average in all the hours we aren't getting paid. All that time on the ground, connecting, delays, NOT PAID."

"We're only paid for time in the air. That flight attendant greeting you at the boarding door, helping you find a place for your bag, guitar, crutches, wedding gown, emotional support pig? They're not being paid," Poole told Travel + Leisure.

Things are even worse for flight attendants when flights are canceled. "At my airline, when a flight is canceled, I lose the hours, meaning I don't get paid. I have to look for another trip — pray I can find another trip — to make up for it on a different day," said Poole.

According to Payscale.com, the average hourly wage for a flight attendant in the U.S. is $20.66 per hour.