Can the radar tell the size of the plane? Or could a large plane say they’re a commuter plane on VFR (just make sure they don’t use the callsign for a plane that the particular FAA sector is already monitoring) and then squawk as directed - and go wherever they want to go without raising suspicions at all?
Not a traffic control radar.
I will have to think about the other question ... IFF is not my specialty ...
Google “radar cross section “.
A small plane has one “cross section” (is ‘smaller’)
A B-52 has a different “cross section” (is ‘larger’) **
** unless it has been modified a’ la “”flight of the Old Dog” ;)