Parachuting a large body of troops directly into a battle zone is one of the most hazardous and complex of military operations. Because of the perils involved, it has been attempted under combat conditions only rarely since World War II. Surprise is vital, or the lumbering transport aircraft could be met with devastating groundfire over the drop zone. The paratroopers, jumping into hostile territory - often at night - can easily become disoriented. Obstacles on an unfamiliar drop zone or weather conditions - high winds, for example - can cause injuries among the jumpers and complicate the next phase of the ground mission. Nevertheless, the mass tactical drop retains a place in today's high-tech arenas of combat, and all of the world's major military powers maintain an airdrop-qualified force. Leaping into enemy territory, a duty fraught with danger and full of unknowns, requires highly motivated soldiers with nerves of steel. That is why a nation's airborne forces are invariably considered the military elite.