Pilots heard making 'meow, meow' & barking sounds in US, get scolding to act professional

Two pilots were heard making 'meow, meow' and barking sounds over an air traffic control frequency at Ronald Reagan Washington National Airport on April 12, after which a person scolded them, saying, "You guys need to be professional pilots." The pilots responded by making more such sounds. "This is why you still fly an RJ (regional jet)," the voice responded.