Peter Steinmetz, a top researcher at the Barrow Neurological Institute in Phoenix, described himself to reporters as a "freedom activist," according to The Arizona Republic.
"I am a peaceful political activist, and my purpose in walking around the airport with my AR-15 rifle was entirely political in nature," he said in a news conference outside his attorney's office. "Put simply, I decided to make the point that a peaceful citizen can openly and responsibly carry a firearm, including an AR-15, for the protection of themselves and their community."
"I wanted to help educate the public and the employees at the airport about this point by allowing them to see a peaceful person responsibly carrying an AR-15 while doing things that people normally do there, like waiting for someone, drinking a cup of coffee," he added.
Carrying a firearm into the airport is not in itself illegal. Steinmetz was arrested on suspicion of two counts of disorderly conduct after a woman and her daughter reported fearing for their safety when the firearm pointed at them. Steinmetz has not faced any charges so far, however.
The neuroscientist had also carried his AR-15 into Sky Harbor Airport last November while picking up his wife. Steinmetz told officers at the time that he was exercising his Second Amendment rights, but on Monday he told reporters that the latest incident had made his point and he didn't plan to do it again.
The Barrow Neurological Institute, where Steinmetz serves as the program director of neuroengineering, put him on administrative leave last week. It's unclear whether and when the institute plans to allow Steinmetz to return to work.
Watch Steinmetz's remarks below, via local TV station KPNX: