Oh dear, where did I go wrong? Years of flying, military and civil aircraft, a period as a military radar controller, experience with the US missile early warning system and not one teeny weeny green UFO, and of course my pilot friends never told me about them, sigh!!!!.
From a practical point of view it is extremely hard, when flying a jet, to spot another object / aircraft on a head on approach for a few reasons. Closing speed is very high, so that with 2 aircraft each at around 500Kts the rate of closure is around 1 mile every 3 seconds. Looking out a cockpit window there is often no point of reference to allow you to focus, (especially at night), and most of the time you do not, because sky is boring.
In 2011 an Air Canada Boeing 767 injured a few passengers when one of its pilots made a violent course change to avoid Venus.
Sorry UI, there are no extraterrestria green UFO's up there, or even down here producing crop circles!
nɥºɾ
