When did the first aerial bombardment by a foreign power on the continental United States take place?

One of the most bizarre incidents occurred during the 1929 Cristero Revolution when an Irishman named Patrick Murphy dropped his bombs on the border town of Naco. He was hired by the rebels to bomb federale trenches at Naco, Sonora.

The barnstormer was hired by to fly bombing missions over the federale lines. For reasons known only to Murphy, he flew unloaded his bombs on Naco, Arizona. One bomb landed on Newton's Garage where it destroyed a Dodge touring car belonging to a federale general who'd stored it on the American side for safekeeping while another hit the Phelps Dodge Mercantile Store. Then an unidentified federale grabbed his .30-06 rifle and took a pot shot at Murphy's plane just as it was making another bombing run. A trail of white smoke unraveled from the plane as it headed down for a crash landing. Murphy escaped to the rebel lines then into the United States where he was quickly arrested by American soldiers, taken to Nogales and locked in jail but was never charged. And he never revealed his reasons for dropping his bombs on Arizona but it did mark the first time the United States had been bombed by someone in the employ of a foreign power.