Upon acceptance of a flight plan for a commercial jetliner flight, a "flight tracking strip" is generated in the departure control tower. This strip contains essentially the same information from the flight plan, but in an abbreviated format. This strip communicates to air traffic controllers along the route information about the flight that assists controllers in directing the pilot. This strip is physically handed off from controller to controller within the same air traffic management facility (such as the local control tower). It is also electronically handed off from one air traffic management facility to another as the flight moves from one airspace sector to another.

Each air traffic management facility has a slightly different look for their flight tracking slips. Below is a generic version of the features of a flight tracking strip.

click on tracking strip blocks for explanation

Every commercial flight is equipped with a transponder. This electronic device is connected to the on-board computer. It transmits coded radio signals to the controller's radar receiver. These signals contain information about the flight: aircraft's identification letters or flight number and its altitude. Upon departure, pilots receive a 4-digit transponder code and set their transponder to that code. The terminology is "Squawk" 1200. The standard transponder code for VFR flights is 1200. When the code is set, the radar "blip" for that flight shows as an enhanced signal on the controller's radar screen. The aircraft is shown in motion on the screen and is followed by a box with the flight's information in it: the data block. This way controllers can visually track each flight as it flies through their designated airspace.

click on data block for explanation

RADAR Data Blocks
Centre Display	TRACON Display