Airport calling tones come from the public address systems used in terminals around the world, where a soft two note chime warns passengers that an announcement is about to start. Online, the sound has been shared as a standalone effect for videos, edits and role play scenes set in airports. It works much like a ding sound effect for notifications, but with a wider echo that suggests a busy hall. Creators keep using it because it communicates location, urgency and travel instantly, without needing footage of an actual airport or a recorded spoken announcement.