1974 White House helicopter incident
On February 17, 1974, Robert Kenneth Preston, a private first class in the U.S. Army, took off in a stolen Bell UH-1B Iroquois "Huey" helicopter from Tipton Field, Maryland, and landed it on the South Lawn of the White House in a significant breach of security. Preston had enlisted in the Army to become a helicopter pilot.
Source: Wikipedia — 1974 White House helicopter incident (CC BY-SA 4.0)