Mandatory GPS Tracking
General aviation aircraft have been doing this for years. I know of at least 3 vendors who offer such service at modest cost: Spidertracks, Spot, and InReach.
Basically, a unit on the a/c sends its GPS coordinates every 10 minutes or to so a satellite which relays it to the tracking company's servers.
The airborne unit often goes on the glareshield, and it includes its own battery that lasts for a few hours if power is lost.