(CNN) — American Airlines says it will not serve alcohol in the main cabin of its flights until January 18, 2022, when the US mask mandate on public transportation is now set to expire.

“We are doing all we can to help create a safe environment for our crew and customers onboard our aircraft,” the airline said Thursday in a memo to employees.

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American suspended alcohol service in the main cabin of its flights earlier this summer, but planned to resume service on September 13 when the transportation mask mandate was originally set to expire.

On Tuesday, the Transportation Security Administration announced that it would extend the mandate through January 18 “to minimize the spread of Covid-19 on public transportation.”

Covid-19 cases have skyrocketed in the United States in recent weeks because of the spread of the Delta variant.

American Airlines also says it is “gaining ground” in helping curb to-go alcohol sales in airports, part of the FAA’s crackdown on unruly airline passengers.

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Unruly airline passengers

On Thursday, the Federal Aviation Administration proposed more than $500,000 in new fines against unruly airline passengers that they say refused to wear masks, hit flight attendants and even threw luggage across the cabin.

And on Tuesday, the FAA said that based on 3,900 reports of incidents, it has opened 682 investigations into possible violations of federal laws.

Many airlines first suspended alcohol sales in spring 2020 to minimize interaction between crew and passengers and to ensure safer flights.

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