THIS is the moment a furious United Airlines passenger punched an airline worker in the face after his flight was allegedly canceled.

Christopher Stuart Crittenden, 54, was caught on camera launching into the violent tirade at Washington Dulles International Airport.

In the footage from Thursday night, Crittenden – who was carrying a bag over his shoulder and wearing a backpack – tries to enter the jet bridge as passengers disembark from another flight.

When a gate agent blocks his way, he snaps.

“I’m done with this bulls***,” he shouts before winding up and landing a brutal punch to the employee’s face.

The airline worker collapses instantly, falling limp to the ground as horrified passengers look on.

Airport officials rushed him to a local hospital for treatment.

Crittenden, a retired Montgomery County Fire Department Captain, was swiftly arrested and charged with assault and disorderly conduct.

Officials also suspect he was intoxicated at the time, Fox 5 DC reports.

Shocking images obtained by TMZ appear to show security officers standing over a handcuffed Crittenden as he sits on the floor near the gate.

“United sucks,” he reportedly shouted while being escorted away.

A fellow passenger claimed Crittenden had already secured a seat on a third flight but was fuming over his travel ordeal, The New York Post reports.

United Airlines confirmed that the Maryland man is now banned from flying with the carrier.

The attack has sparked fresh calls for tougher measures against unruly passengers.

The International Association of Machinists and Aerospace Workers (IAM), which represents airline employees, slammed the incident, saying workers deserve a safe environment.

The union said: “Our members deserve a workplace where they can focus on providing excellent customer service — not one where they fear being attacked by passengers.

“This latest incident is yet another example of the unacceptable rise in violence against frontline airline workers, and immediate action is needed to address it.”

IAM warned that violence against airline staff is increasing with “minimal repercussions” for offenders.

“Any disruptive behavior—whether due to intoxication, aggression, or other factors — introduces unnecessary risks to airline operations,” the union added, urging the Department of Justice to enforce stricter penalties.

United Airlines and the Metropolitan Washington Airports Authority have yet to comment on the attack.