Zero Length | Launch of a Republic F-84G Thunderjet from a Trailer in 1955

The zero-length launch system or zero-length take-off system (ZLL, ZLTO, ZEL, ZELL) was a method whereby jet fighters and attack aircraft could be near-vertically launched using rocket motors to rapidly gain speed and altitude. Such rocket boosters were limited to a short-burn duration, being typically solid-fuel and suitable for only a single use, being intended to drop away once expended.