Nothing can stop the attack of aircraft except other aircraft.
Meaning of the quote
The quote means that the only way to stop an attack by aircraft is to use other aircraft. No other defense, like guns or missiles, can stop an aircraft attack. Airplanes are the best way to fight against other airplanes.
About Billy Mitchell
William Lendrum Mitchell was a pioneering United States Army officer who played a crucial role in the creation of the U.S. Air Force. He advocated for increased investment in air power and conducted bombing runs to demonstrate the ability of bombers to sink battleships, which led to his court-martial and resignation from the service. Despite this, Mitchell was honored after his death, including having a military aircraft design named after him and an airport in Milwaukee, Wisconsin.