The program was previously paused due to the pandemic and its restart comes amid an increase in unruly passenger incidents on flights.
The voluntary training provides flight crew members with techniques "for responding against an attacker in a commercial passenger or cargo aircraft," including self-defense measures and ways to identify and deter potential threats.
"While it is our hope that flight crew members never have need for these tactics, it is critical to everyone's safety that they be well-prepared to handle situations as they arise," LaJoye said.
The Federal Aviation Administration has received approximately 3,100 reports of unruly behavior by passengers this year, including about 2,350 reports of passengers refusing to comply with the federal face mask mandate.
While many of these incidents are occurring on flights, they are also happening at security checkpoints. The agency is reminding travelers to "be patient."
"Passengers do not arrive at an airport or board a plane with the intent of becoming unruly or violent; however, what is an exciting return to travel for some may be a more difficult experience for others, which can lead to unexpected, and unacceptable, behaviors," LaJoye said.
Sara Nelson, president of the Association of Flight Attendants-CWA, the union representing flight attendants, hailed the return of self-defense training and said it should be "mandatory and repetitive."
"Flight Attendants are aviation's first responders and last line of defense," Nelson said in a statement. "Following September 11th, in November 2001, Congress mandated self defense training as part of flight attendant initial and recurrent training."
"We applaud TSA for restarting the program as unruly passenger incidents hit an all time high," she added. "This should send a message to the public as well that these events are serious and flight attendants are there to ensure and direct the safety and security of everyone in the plane."
The TSA pointed to two recent incidents where passengers assaulted Transportation Security Officers, or TSOs, during the screening process. Both passengers face a potential civil penalty of up to $13,910 for each violation of TSA security requirements, the agency said.
"I'm asking people, the American public, to do is be patient with these TSOs as they're trying to ensure your safety as you go those flights, and as you come off," Everett Kelley, national president of the American Federation of Government Employees (AFGE), the union that represents TSOs, said in an interview with ABC News.
ABC News' Mina Kaji contributed to this report.