A passenger was arrested after assaulting a Southwest flight attendant on a Sunday morning flight.
The flight attendant lost two teeth and and sustained injuries to the face.
According to The Washington Post, the passenger ignored standard instructions that the plane was about to land in San Diego, which allegedly led to the attack.
When the plane landed, the passenger was taken into custody by authorities.
According to Lyn Montgomery, the president of the Transport Workers Union Local 556, a union representing Southwest flight attendants, passenger non-compliance events became more aggressive.
Montgomery wrote to Southwest Airlines chief executive Gary Kelly. listing the union's grievances.
"This past weekend, one of our flight attendants was seriously assaulted, resulting in injuries to the face and a loss of two teeth. Unfortunately, this is just one of many occurrences. We cannot tolerate our beloved cohorts being abused in such a manner.
"Today’s travelling environment requires a new level of firmness in both tone and direction to ensure proper control in the cabin of our aircraft as the attitudes and behaviours of the flying public have, unfortunately, declined," the letter read.
Montgomery said Southwest Airlines had the responsibility of being front and centre on the matter.
The union suggested that the airline "publicly denounce passenger misconduct and associated disruptive/violent behaviour".
"Inform the public of the consequences for misconduct and abuse toward our employees. Demonstrate that interference with crew members' duties, including intimidation, threats of violence, and outright physical aggression, will not be tolerated.
"One tool to better utilise would be the Southwest Airlines restricted travellers list. The flying public needs to understand that egregious behaviour will result in being banned from flying with Southwest Airlines," Montgomery said.
She also suggested that the US government increase the number of Federal Air Marshals (FAM) onboard.
"Request that the Air Marshals get involved and take action when a threat to a cabin crew member is present. We know from our colleagues in the industry that this problem is not unique to Southwest Airlines, so I hope you will bring this matter before Airlines for America (A4A) to initiate a quick and immediate remedy," said Montgomery.