Why do people yell Geronimo when they jump off something?

World War II paratrooper Aubrey Eberhardt was the first to scream "Geronimo!" while jumping from great heights. Retired First Sergeant Ed Howard explains how it happened in his essay entitled "Paramount's 1939 Western Geronimo...A Forgotten Movie With a Giant Legacy." In 1940, the United States' first Parachute Test Platoon was formed. It consisted of 50 volunteers who trained in the sweltering heat of Georgia's Fort Benning. The days were mighty hot, so the paratroopers wanted to stay cool in the evening. One night, Private Eberhardt and three friends watched the movie Geronimo at a local (air conditioned) theater. After the film, the group discussed the jump they were to make the following morning. According to Howard, one paratrooper asked Eberhardt if he believed he could jump "without fear." Eberhardt, eager to prove his toughness, said he'd show everyone he wasn't afraid by yelling "Geronimo!" as he jumped. Eberhardt believed that if he had the presence of mind to remember the word, it would prove he wasn't scared. Questionable logic perhaps, but we're going with it. Long story short, Eberhardt jumped, yelled "Geronimo!" as promised, and the shout quickly caught on with his fellow paratroopers. Some time later the phrase was outlawed because officers felt it would draw unwanted attention to paratroopers landing in hostile territories. That said, the "Geronimo" motto is still seen on certain military insignias, so Eberhardt's legend lives on.