[myself248]

Bingo. Air-gapped machines, by definition, have no connection to each other. Not so much as an audio cable between them. Everything that goes back and forth is manually transferred, either by eyes-on-one-screen-hands-on-the-other-keyboard, or by sneakernet typically of media which may be inspected at yet a third station en route.

This is a proxy or a bastion host, no more, no less. Calling it an airgap, even in "scare quotes", is clownishly terrible and serves no purpose beyond polluting the language.