FCC in the US have explained repeatedly:
It is legal in the US, if the pilot is not a ham operator, If
1) a ham radio operator on the ground (associated with the used ham callsign) is constantly monitoring the used APRS frequency, and
2) the groundbased person is located within range of the aircraft transmissions, and
3) the groundbased person orders the pilot to switch off the APRS, in case of malfunction (continous transmission etcetera), for example by the normal VHF radio for aircraft.
The same is valid for cars (if the driver is not a ham operator).
Digipeaters should not be used when transmitting from an aircraft.
"Tactical call sign" is permitted, if the callsign is sent in the "comment".
A summary:
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If a ham responsible for the club callsign, at the club house, during a local flight close enough to the club-house, supervises the APRS freq, and tells the pilots to switch off their trackers in case of problems, it is legal in the US, even when the pilot is not a ham.