World War II may have definitively proved that battleships and other big-gun surface warships were no longer the dominant naval weapons, but the battleship's days were numbered well before the start of the war.
In a high-profile test that culminated on July 21, 1921, aviators led by Brig. Gen. William "Billy" Mitchell sank three captured German warships — demonstrating once and for all the advantage that aircraft have against warships.
The test embarrassed the Navy and its significance was hotly debated, making it one of the earliest examples of US military inter-service rivalry. It was also a glimpse of the tactics that would transform naval warfare over the following decades.
