An Aircraft Communication and Addressing Reporting System (ACARS) compatible transmitter is disclosed. In embodiments, the transmitter receives outbound (e.g., downlink or uplink) ACARS messages from aircraft end systems and compresses the header/trailer (H/T) and/or text payloads of ACARS blocks (e.g., text messages) or ACARS acknowledgements (ACK)) prior to transmission. For example, the transmitter compresses ACARS blocks by removing fixed markers and encoding variable fields. The transmitter parses incoming text payloads to determine their character distribution and selects a radix alphabet including the ASCII characters used in the text payload. The transmitter converts the ASCII characters to binary characters of the corresponding alphabet based on the selected radix base, assembling a compressed message block for transmission based on the compressed H/T component and/or text payload, adding a link layer header to indicate the selected radix base to the ACARS destination for decompression of the received compressed message.