The Federal Aviation Administration is proposing more than $100,000 in fines against four plane passengers, including one who had to be physically restrained and handcuffed after hitting and pushing a flight attendant on a flight from Honolulu to Seattle.

As a result of the incident on a Delta Air Lines flight Dec. 23, the man faces a $52,500 fine. According to the FAA, the man allegedly tried to open the cockpit door and refused to follow instructions from crew members. At one point, after the man allegedly hit a flight attendant in the face and pushed him to the floor, the man then threatened and charged the flight attendant as he tried to restrain the man. Flight attendants,, with the help of another passenger, put plastic handcuffs on the man. The man was able to free himself from one of the handcuffs and allegedly struck the flight attendant in the face a second time. The passenger was taken into custody by police after the plane landed, officials said.

In a second incident on Jan. 1, a passenger on a Southwest Airlines flight from Phoenix to Chicago faces a $27,000 fine after claiming that he had a bomb and was going to blow up the plane, authorities said. After taking his seat on the plane, the man allegedly began yelling and banging his hands on the seat in front of him. He then threatened to kill someone before talking about a bomb, officials said. Flight attendants moved the man away from other passengers, and the flight was diverted to Oklahoma City, where the man was taken into custody.

A JetBlue passenger on a Feb. 5 flight from Fort Lauderdale to Las Vegas faces an $18,500 penalty after drinking several mini bottles of alcohol he’d brought with him, despite being told by a flight attendant that he could not drink the alcohol, officials allege. Flight attendants also told the passenger he had to wear his mask when not eating and drinking while on the flight, but the man refused to follow their instructions, according to officials.

A woman on a Feb. 15 Allegiant Air flight from Fort Lauderdale to Knoxville, Tenn., allegedly refused to follow instructions to wear a mask while on board, authorities say, and faces a $9,000 fine from the FAA. The woman continued to defy flight attendants’ instructions to wear her mask properly, allegedly cursing at crew members. During the flight, the woman got up to use the bathroom, and when she found it was occupied, sat in an exit row to wait. When told by a flight attendant, she couldn’t sit in the exit row, the passenger, who was still not wearing a mask, allegedly screamed at the flight attendant, officials said.

Federal law prohibits individuals from interfering or physically assaulting aircraft crew or others on the aircraft because it can threaten the safety of a flight by disrupting or distracting crew members from their work. Those found in violation receive enforcement letters from the FAA and have 30 days to respond to the allegations. The agency does not identify individuals who face civil penalties.

In January, the FAA announced that it would take more aggressive action against passengers who refused to follow crew members’ instructions on commercial aircraft. The special order, signed by FAA Administrator Steve Dickson, followed several in-flight disturbances linked to the Jan. 6 riots at the U.S. Capitol. The move, which was set to expire in March, was extended indefinitely.

Earlier this month, FAA officials said they had received more than 1,300 complaints about unruly passengers since February and are investigating at least 260 cases in which passengers did not comply with orders. The Transportation Security Administration, which had the authority to enforce a federal mask mandate on airplanes, at airport security checkpoints and in other transportation settings, said it has received 2,000 reports of people refusing to wear masks when instructed, the majority of which involved people on airplanes.