(CNN) — Airlines and two unions representing flight attendants are concerned about in-flight security as the pro-Trump rioters who stormed the US Capitol Wednesday leave the Washington DC area.
American Airlines and United Airlines have both increased staffing at the DC-area airports where they operate. American is also suspending alcohol service on its flights to and from the region.
The Association of Flight Attendants-CWA (AFA) International, which represents nearly 50,000 flight attendants at 17 airlines, said the rioters should not be allowed on flights home.
"Their violent and seditious actions at the Capitol (Wednesday) create further concern about their departure from the DC area," AFA president Sara Nelson said in a statement. "Acts against our democracy, our government, and the freedom we claim as Americans must disqualify these individuals from the freedom of flight."
The union that represents American Airlines flight crew, Association of Professional Flight Attendants (APFA), also issued a statement about in-flight incidents.
"We are incredibly concerned about recent politically motivated incidents on board passenger aircraft," read the release from the APFA president Julie Hedrick. "Regardless of one's political beliefs, the cabin of a commercial aircraft must, out of necessity, be a calm environment for the safety of everyone onboard."
One video shared on Twitter showed Trump supporters yelling and arguing with other passengers aboard an American Airlines flight. In addition, Washington Post photographer Jabin Botsford posted video to Twitter of two passengers being removed from a flight to DC, and other videos showed pro-Trump supporters heckling Sen. Mitt Romney in the airport and on a flight.
"The mob mentality behavior that took place on several flights to the D.C. area (Tuesday) was unacceptable and threatened the safety and security of every single person onboard. It will not happen again," Nelson said.
President Trump had encouraged his supporters to come to the capital to protest the certification of President-Elect Joe Biden's election win. Once there, a large group of supporters attacked Capitol Police officers and violently forced their way into the Capitol building on Wednesday, leaving four people dead.
Altercations aboard flights earlier this week
APFA spokesman Paul Hartshorn, Jr. told CNN Travel that the union had suspected there might be a rise in unruly passenger behavior this week, but not on "such a threatening and violent level."
On flights into and out of Washington, several flight attendants on several different airlines have been "forced to confront more than one passenger on board who's verbally and or physically abusive to the crew, and to the passengers," said Hartshorn. "That's not something we should be dealing with."
Hartshorn said some air crew who are members of APFA had expressed concern about flying DC routes over the upcoming days. In some cases, they've subsequently been moved onto different trips.
"It's an incredibly scary and dangerous situation," he said. "And it's a huge problem these past few days, and we anticipate it being a problem through the weekend, as these people fly home from the Washington area."
But banning travelers who'd been involved in the violence would be "a Herculean task," he said.
"If the airline is aware of someone that has been abusive on the ground, involved in rioting, and destruction of property and dangerous behavior, that if the airline was aware of it, they absolutely should not be allowed to fly home from Washington on our airline. I believe, again, that that's very difficult to monitor."
Nelson, the AFA president, called on airlines and government agencies to step in for security.
"Airlines, in coordination with TSA, DHS, FAA, DOT and law enforcement must take all steps to ensure the safety and security of passengers and crew by keeping all problems on the ground," she added.
American Airlines stops alcohol services on DC flights
American Airlines says it is taking several new "precautionary" measures, including no longer serving alcohol on flights to and from Washington.
American Airlines and United said their crew members with overnight layovers in the DC area will not stay in downtown hotels. Delta Air Lines and Southwest Airlines declined to specify any operational changes.
In an internal memo to Delta employees on Thursday, obtained by CNN, Delta CEO Ed Bastian called out the "shocking violence at the US Capitol," and said protest must not "cross the line into violence and insurrection."
"Respect and civility to others on our planes, at our airports, in our workplaces, and in our society -- even if we have differences of opinion -- has always been a requirement for our people and our customers," Bastian wrote.
The four major airlines also said they have been in touch with law enforcement authorities and the Transportation Security Administration.