ACARS stands for Aircraft Communications Addressing and Reporting System

ACARS allows air/ground datalink communications for Airline Operational and Air Traffic Communications (AOC and ATC). It is a digital "texting" system, allowing aircraft to automatically send and receive short messages with ground stations, automating data like position, weather, and system status to improve flight safety, efficiency, and reduce voice radio use. Datalink messages are carried by VHF, HF or SATCOM transmissions, with SATCOM providing the highest data rate.

Aircraft datalink technology was developed in the late 1970's by a company called Aeronautical Radio Inc (ARINC). ACARS, developed by ARINC, became the industry standard aircraft datalink system which is still used by airlines around the world today.