That's already inexpensively available; it's called Automatic Flight Following (AFF). It's small, easily installed, and inexpensive to operate . Those that I am familiar with send a GPS position, including altitude, every 2 minutes via satellite to a ground station. I believe that track, not heading, and ground speed are calculated using the previous datum. The data are available for display on a digital aviation chart, map, Google Earth, etc. It's been available for many years. All of the US Federal fire fighting aircraft have them and that includes contractor's aircraft. I suspect that most US Federal aircraft have them no matter what their use.
The system that I've used will tag the last datum received if it has been more than 10 minutes since the last one and the icon on the display will be red. Probably the system could send alter text messages and emails, too. The display allows for viewing the last position of many aircraft or the track of a single one from an arbitrary time to the most recent datum.
This certainly helps discovery of a problem and provides a good starting point for SAR efforts.