What information an aircraft responder must give to mode S ground receiver
From Mode-S.org

An ADS-B message is 112 bits long:


+--------+--------+-----------+--------------------------+---------+
|  DF 5  |  ** 3  |  ICAO 24  |          DATA 56         |  PI 24  |
+--------+--------+-----------+--------------------------+---------+


DF is the downlink format, ICAO is the 24-bit ICAO identifier of the aircraft, DATA is the message being transmitted, and PI is the parity/interrogator ID.

There are a number of different message types available:



The messages transmit things like position, altitude, turns, track, airspeed, roll angle, turn rate, etc. But they do not contain any information about the originating airport or the destination.