TSA.Gov
Everyone who travels by air goes through airport security checkpoints. These checkpoints are operated by Transportation Security Officers from the Transportation Security Administration.
The checkpoints are there to make sure that terrorists can’t bring anything aboard the plane that would enable them to take it over or destroy it. These are called “prohibited items” and cannot be brought to a checkpoint, into the secure area of an airport, or aboard an aircraft.
Not only do all passengers go through checkpoints, their checked baggage is also screened. This may happen out of passengers’ view depending on the physical configuration at each airport.
It’s a good idea to prepare before you arrive at the airport so that you move more quickly and efficiently through the security process. Here are some suggestions to help make the process as smooth as possible.
TSA.Gov

Two weeks ago, I went to Canada, when I tried to get my boarding pass at the airport machine, I was redirected to the air line clerk. However, when I returned from Canada, I had no problem getting a boarding pass at the machine. Could you explain me why that happens in my own country? Since my name has never been associated with any kind of illegal activities, as a retired NYC civil servant. Is there anything I can do to correct that?
Why hasn’t anyone thought of the obvious? We have mens and womens restrooms. Why in the world couldn’t you have mens and womens body scanners at the end of the security line in airports, with the assurance of having the same gender viewing the monitor? I mean, it’s not rocket science! If we have to be viewed nude it should at least be by someone of the same gender!!!!!!!!!!!!!! No wonder everyone is mad about these machines. I don’t have an answer though when it comes to digitally stripping children. I guess anyone viewing that monitor, even momentarily, should go to jail, I don’t know. You can figure that one out.