Airborne forces

Airborne forces are ground combat units carried by aircraft and airdropped into battle zones, typically by parachute drop. Parachute-qualified infantry and support personnel serving in airborne units are also known as paratroopers.

The main advantage of airborne forces is their ability to be deployed into combat zones without land passage, as long as the airspace is accessible. Formations of airborne forces are limited only by the number and size of their transport aircraft; a sizeable force can appear "out of the sky" behind enemy lines in merely hours if not minutes, an action known as vertical envelopment.

Airborne forces typically lack enough supplies for prolonged combat and so they are used for establishing an airhead to bring in larger forces before carrying out other combat objectives. Some infantry fighting vehicles have also been modified for paradropping with infantry to provide heavier firepower.

Protocol I of the Geneva Conventions protects parachutists in distress, but not airborne troops. Their necessarily-slow descent causes paratroopers to be vulnerable to anti-air fire from ground defenders, but combat jumps are at low altitude (400–500 ft) and normally carried out a short distance away (or directly on if lightly defended) from the target area at night. Airborne operations are also particularly sensitive to weather conditions, which can be dangerous to both the paratroopers and airlifters, and so extensive planning is critical to the success of an airborne operation.

Advances in VTOL technologies (helicopter and tiltrotor) since World War II have brought increased flexibility, and air assaults have largely been the preferred method of insertion for recent conflicts, but airborne insertion is still maintained as a rapid response capability to get troops on the ground anywhere in the world within hours for a variety of missions.