* During the Vietnam War, the US made extensive use of modified Ryan Firebee target drones for reconnaissance over North Vietnam. The "Lightning Bugs", as the reconnaissance Firebees were known, were effectively abandoned after the conflict, but they did lead to interest in development of "high-altitude long-endurance (HALE)" drones -- not merely to obtain long range, but also persistence over an operational area.
From the 1990s, the US put the HALE drone concept into operational service, acquiring the General Atomics "Predator" and Lockheed Martin "Global Hawk" drones. This document describes these drones and their origins, and also describes other HALE drones developed by the US. A list of illustration credits is included at the end.
