Air Bridge
An air bridge is a type of military method used to evacuate large numbers of persons in a short time period.In essence it is a corridor of fast moving aircraft that fly backwards and fowards between a pick up and drop off point, flying almost non stop until all persons are evacuated.
Air bridges are used in times when the speed of evacuation is more important than safety.
Safety
There are serious concerns over the safety of air bridges since they involve the use of aircraft for as much as 48 hours, leading to mechanical wear and tear, and failure.
Since aircraft only stop long enough to refuel engines does not have a power down period, which often leads to overheating.
In general an air bridge is launched from an aircraft carrier, but does not involve the Combat Air Patrol (CAP) or alert fighters.
There are also concerns regarding pilot fatigue.
Use
The most famous air bridge was that used to evacuate the last of the US forces from Saigon, Vietnam, before overrun by Northern forces.
More recently the United Kingdom used an air bridge to evacuate over 10,000 citizens from Lebanon.