[Stig Jarlevik]

The WW 1 Lufbery circle was the idea to form a defensive circle where each aircraft in the circle
protected the rear of the aircraft in front of him.

If an enemy aircraft tried to enter behind any of the aircraft in the circle the allied aircraft
behind would thus shoot it down

In WW 2 the idea to do so was more or less dead since the performance of aircraft had
increased dramatically. New ways of entering combat made such circles outdated.

At least early in the war it was still in use especially by fighters having less good performance.

Cheers
Stig