Neal Strassner was going through the checkpoint at Greater Rochester International Airport when the staff member handed him a torn piece of paper.
The note read: “You ugly”, leaving Mr Strassner dumbfounded.
Despite the incident happening in late June, Mr Strassner only recently obtained a copy of security footage from that day through a Freedom of Information Act.
The video shows him stopping and looking at the guard as she slips him the bizarre message.
After he passed through the checkpoint and began walking away, Strassner said he heard the worker yell back at him, “You going to open the note?” before bursting out laughing.
"I was more confused than anything," Strassner told NBC. "I kind of just looked at it and thought, 'That was weird.'"
The tech worker has said that while the incident didn’t upset him, it could have had a negative effect on someone else.
“You never really know where somebody is in their day or their head,” he told ABC 13.
"The more you think about it, the more you realise it's easier to smile than to do this."
Strassner also said he believed he wasn’t the only person to have been given such a note.
"At the end of the video I requested, she literally just takes a pen out of her pocket and starts writing another one,” he said. “So, I know I wasn't the only guy that got one.”
Transportation Security Administration (TSA) said it had "zero tolerance for this type of behaviour."
It added that the employee, who was a contractor from an external firm, had been fired by the company.
He added that he would not allow one bad experience to sour his opinion of Greater Rochester International Airport, which has free classic arcade games he likes.
"I fly out of there all of the time,” he told NBC. “They're actually a pretty good airport.
"Out of all the airports I go to in the country, it's one of my favourite."