The suspect is still on the loose.
Police say the suspect had a pellet gun and approached two employees, who were in an unmarked RDU authority car. The man tried to rob the employees and there was a struggle.
The two employees were shot, but were not seriously injured.
The Highway Patrol issued an alert or BOLO for the suspect who was described as wearing a camouflage face mask. He fled the parking lot on foot after the attempted hold-up.
Two similar crimes happened in the park and ride in October, according to RDU authorities.
"We've parked in three before and we haven't had a problem, but it is kind of scary to think about what could happen," air traveler Kristi Dean said.
"I've always felt safe here at the airport," air traveler Jimmy Dean added. "I mean we haven't had any problems."
But with three armed hold-ups in two months, they say they are starting to wonder about security at other RDU parking facilities, including the main deck between the two terminals.
"I don't know if I've seen a security officer since we've outside the airport," Kristi Dean said.
RDU officials say there is plenty of security all over the airport.
"Whenever an incident happens -as rare as they are- we do take those opportunities to investigate them, look at them and see if there are changes we need to make to prevent the same thing from happening again," RDU spokesperson Mindy Hamlin said.
Meanwhile, the incidents are under investigation. Authorities say none of the suspects in any of three crimes have been arrested.