I applied online. I interviewed at TSA (Transportation Security Administration) (Oakland, CA) in Jan 2016
Interview
Very long process. Keep checking your dashboard for changes, apply elsewhere because they are sloooow. Airport assessment was pretty easy, usual customer service type questions. There's two people in the room with you, rest of the stuff was pretty easy. Go well dressed. People showed up in tennis shoes, not good. Background is a little difficult to get through, the filling out of forms etc. Process is also slow.
I interviewed at TSA (Transportation Security Administration) (Miami, FL) in Feb 2019
Interview
Two interviews and you have to do a computer test. If passed you move on to the next step in the hiring process. This was 5 years ago, not sure if the process is still the same but, this is how it was done before.