On a sunny day (Sat, 25 Jul 2009 22:31:04 +1000) it happened Sylvia Else wrote in :
By the definition, or meaning of, 'inconspicious', from:
The man was not very noticeable in the cloud of smoke.
You can hide tanks, soldiers, even planes, in a cloud [of smoke]. Set up a bush fire to hide an advancing army. Much cheaper and better then any hightech not yet, and perhaps never, existing solution. Clouding radar with alu foil strips is the same idea, hiding aircraft or aircraft's exact position.
From a technical POV, I seriously doubt the current proposed cloaking systems that are based on negative reflective index if I understood it right, will work over the full visible spectrum, let alone in radio and IR at the same time. So, back to the smoke :-)