In article .com,
"Louis L. Perley III" wrote:

A company called ThinkGeek is now selling a aircraft tracking laser. It
hooks up to the internet via a number of sources online to identify
aircraft in the area and then tries to target them. It plugs into your
computers USB port. Not a bad price at that!

This triggered a memory of being told two or three decades ago that a
precision laser aircraft tracking radar, in combination with cooperative
corner cubes on the aircraft to increase the radar return, was used to
carry out precise performance verification or certification tests on
commercial aircraft in connection with aircraft purchase or delivery.

Anyone know if this is still the case?