Originally Posted by
MSPeconomist
To answer the general question asked in the thread title, the previous flight/track incoming aircraft function sometimes displays results that are obviously wrong, such as an aircraft arriving into the wrong airport. Also, it might disagree with the carrier's flight status information due to differences in the definitions/measurements used: airline tracks arrival and departure at gate while flightaware.com focuses on when the plane takes off and lands.
^ The timeline feature of flightstats.com can also be another helpful data point, particularly for domestic US flights.