Definition
The small aircraft symbol displayed in the center of an attitude indicator (or heading indicator) that represents your own aircraft. Its position relative to the horizon bar shows the airplane's pitch and bank attitude.
Plain English
A tiny aircraft figure on the attitude indicator face that stands in for your real airplane, so you can see how its nose and wings are pointed compared to the horizon.
Context Anchor
Seen during the instrument check before taxi, during taxi, and before takeoff when confirming that the attitude indicator looks normal and responds correctly.
Derivation
Miniature means a small version or small representation of something. Here, the instrument uses a small aircraft symbol to represent the full-size airplane you are flying.
Why Pilots Care
On many attitude indicators, the miniature aircraft can be adjusted up or down to align with the horizon bar in level flight. If it is set incorrectly, every pitch reference you fly will be off, which matters most during instrument approaches and climbs in low visibility.
Intuition Check
The miniature aircraft is not another airplane and not traffic. It is the symbol for your own airplane on the attitude indicator.
Example Sentence 1
During the instrument check before taxi, the pilot confirmed the miniature aircraft was aligned with the horizon bar on the attitude indicator.
Example Sentence 2
As the aircraft entered a standard-rate turn the miniature aircraft showed a bank angle matching the turn coordinator.