What is the origin of the idiom "out of the loop" and when to use it?

The idiom "out of the loop" likely originated in aviation and military contexts, where it referred to a pilot or personnel who was not included in a particular flight plan or information loop. This phrase is used to describe a person who is not privy to the current information, developments, or decisions within a specific group, organization, or social circle. It implies a lack of awareness or being excluded from important communication.