I can definitely amplify here.
As I mentioned, our task is to detect, track, identify and characterize, and from there to assess the threat related to any unknown tracks coming across the NORAD airspace and within the NORAD areas of operation.
As part of that, our folks on the ground are using sensors—mostly radar sensors—to detect anything that may be on the approaches of North America, as well as leveraging sensors for what may be in the airspace.
The reality is that the size of Canada and the U.S. doesn't allow for full coverage of the airspace. We have a huge land mass. In this case, normally we're going to have the ability to detect the standard air traffic, which would normally communicate with the air traffic controls. They would be “squawking”, or transmitting a code that would be picked up by air traffic control to identify the aircraft itself.
In the case of general aviation, that is what we call a “1200 squawk”, which is saying that it's a general small aircraft operating in the vicinity of the location.
I haven't actually gone into the book to look at the specific Transport Canada or U.S. Federal Aviation Administration regulation, but I know that balloons or other objects ought to be transmitting a position and an altitude location so that we can actually distinguish between them and potential air traffic and enhance safety as well.
In this case, those objects and the high-altitude surveillance balloon of the PRC were not in communication—were not squawking—and therefore were unknown to us. That's why we first of all took action to identify them. Then, because of the threat they posed to civil aviation, which was a concern to both governments, we actually took them down under the direction of both governments.