This chime is the standard two-tone cabin signal used on Airbus A320 aircraft to alert passengers when the seatbelt sign changes. The same recording style is shared widely in royalty-free sound libraries, where travel creators find it for vlogs and edits. Because almost every frequent flyer has heard it in real life, it has become a shorthand online for boarding, flying and landing, and it still works because it needs no explanation to be understood instantly by viewers.