(NEXSTAR) – It probably goes without saying, but 2021 has not been an exemplary year for airline passengers.

Since the beginning of 2021, the Federal Aviation Administration has received more than 5,700 reports of in-flight disturbances caused by unruly passengers, over 4,100 of which involved (at least in part) travelers violating COVID-prompted mask requirements.

A bunch of these rowdy passengers came out swinging in the first few weeks of 2021. In early January, FAA administrator Steve Dickson noted a “disturbing” increase in reports of bad behavior, specifically noting an uptick in cases following the insurrection at the U.S. Capitol on Jan. 6. The FAA subsequently issued a “zero tolerance” policy for bad behavior, warning of legal enforcement action against any passenger who assaults, threatens, or otherwise interferes with the duties of the flight’s crew.

The rate of disturbances began dropping over the next few months, but the frequency of such incidents still remains “too high,” according to the FAA — and much higher than it was in 2020.

Police and FAA officials have released details of the most egregious or violent suspects, some of which have been referred to the FAA for criminal prosecution. Other times, fellow passengers have captured these rowdy incidents on film, showcasing just how volatile they can be.

Here’s a look at some, but by no means all of 2021’s worst offenders.

In-seat bathroom break

A passenger flying with Alaska Airlines in March struck a flight attendant and urinated in his seat after refusing between “eight to ten” requests to put on his mask. The passenger, who also urinated on a fellow traveler’s bag, was charged with interfering with a flight crew.

Assault on a flight attendant

In May, a passenger flying with Southwest Airlines struck a flight attendant and chipped three of her teeth. (The flight attendant also suffered bruising near the eye and a cut that required stitches.) The incident prompted the president of TWU Local 556, a union representing over 15,000 Southwest flight attendants, to urge Southwest CEO Gary Kelly to help end the “intolerable level” of disruptive incidents they were seeing.

The passenger pleaded guilty in December to interfering with a flight crew, a charge that carries a possible sentence of up to 20 years in prison and $250,000 in fines.

Can I have your attention?

A Delta Air Lines flight was diverted in June after an unruly passenger began trying to make announcements over the plane’s loudspeaker. Several passengers and crew members attempted to wrestle him away, and were ultimately able to restrain him in the aisle, video shows. At the time, witnesses were unsure if he was trying to open the cabin door or hijack the plane, though Delta later claimed he had attempted neither.

Duct-taped to her seat

A passenger aboard an American Airlines flight in July was forcibly restrained to her seat with heavy-duty duct tape after allegedly assaulting and biting a flight attendant while trying to open the boarding door. Footage of the woman bound to her seat was later shared to — and deleted from — TikTok, but not before amassing over 4 million views.

The woman was met by law enforcement upon landing, American Airlines confirmed. She was also placed on the carrier’s no-fly list.

Belligerent and gropey

In late July, a 22-year-old passenger flying with Frontier Airlines needed to be restrained to his seat after consuming alcohol and becoming belligerent, police say. Prior to being taped to his seat, the young man removed his shirt and groped the breasts of multiple flight attendants. Other passengers also filmed him bragging about how rich his parents were before he ultimately punched another crew member in the face.

The unruly passenger was arrested upon landing, and charged with three counts of battery.

Choking a flight attendant

A passenger aboard a JetBlue flight in September attempted to storm the cockpit, reportedly after being unable to make a call on his cell phone. A flight attendant was able to intervene before the man reached the cockpit door, at which point the passenger managed to grab hold of the flight attendant’s necktie and choke the crew member with it. The man was eventually restrained with seat-belt extenders and the aforementioned necktie, per an FBI affidavit. The passenger later faced charges of interfering with a flight crew.

‘I will break your neck’

A combative United Airlines passenger was ejected from a flight to California in October after appearing to threaten a flight attendant and a few of the other passengers. Witnesses say the man became agitated after being asked to wear his mask, and video of the incident shows him threatening both a flight attendant and another man who appeared to be wearing a badge.

“Mind your business. Mind your business. Because I will break your neck,” the unruly passenger told the man with the badge.

The passenger who filmed the incident claims the unruly man was eventually escorted off the plane by police after making further threats to passengers and crew.

Impromptu announcement

Also in October, a passenger flying with Delta Air Lines was escorted to the back of the plane after pulling out her own microphone and amplifying device in an attempt to lecture her fellow fliers on “the reason the pandemic started.” In viral footage of the incident, the woman is also heard claiming that the other travelers were “enjoying” her antics because she’s “not terrible to look at.”

The woman was allowed to retrieve her dog — who had “better sense” than the other passengers, she said — before being relocated away from her row.

Cookie thief

In November, the FAA levied a fine of $32,000 against a single Horizon Air passenger who “punched and screamed at her husband and son, repeatedly” before throwing trash at a crew member. The kicker? The FAA also noted that she “snatched cookies from a nearby passenger” during the incident.