A website called Flight-Viz allows users to track planes in real-time and view their flight paths in 3D from a cockpit perspective. The feature uses live ADS-B data and provides a first-person view with real buildings, terrain, atmosphere, and a HUD showing altitude, speed, and heading. Users can access this feature by clicking on a plane on the map, then selecting the 'Cockpit' option from the menu. The website has received feedback and suggestions for improvement from users.