What is the start/stop criteria for recording Track Logs with automatic recording?

If you have Track Logs set up to record automatically (More > Settings > Track Log > Enable Auto Start/Stop), AND ForeFlight is running in the foreground, then Track Logs will be recorded automatically for each of your flights if you have a GPS source.

The criteria for how this works is complex and has many variables.  As a good ballpark, you can generally expect the Track Log to record starting 30 minutes prior to takeoff (60 knots) and for 15 minutes after you land and slow below 40 knots.