No it's an FAA requirement that all planes from military(non combat) to your grandfather's prop plane to broadcast/transmit at a minimum their location(geo coordinates, altitude and speed), As well as your plane's tail ID number and planned route (but that's not always public). This is to avoid mid air collisions, and allow flight towers /FAA to direct air traffic. This is all done through a device in the plane, it can be turned off and on.

There are websites that collect all this data and that allow you to see all this data from your web browser. Just Google "air traffic radar map", and you'll see tons of options. ( I prefer flightradar24.com )

When the US government or military conduct operations they want kept out of the public eye, they have their planes turn off this, thus no longer "squawking" and invisible to just about everyone except themselves.