air force one. >> guest: angel is the code name for air force one. that was very, very surreal. that those were really moments aboard the plane. >> host: offit air force base. what is this moment? >> guest: secret service agent standing post outside of the room where inside the president was receiving a full briefing from military commanders there. >> host: this is one of the occasions you were not allowed in? >> guest: exactly. >> host: did you have clearance, top secret clearance. >> guest: i did. i had top secret clearance. >> host: you had to go through the background check and everything? >> guest: exactly, exactly. >> >> what: is that process like? >> guest: very intense. they call everyone. >> what time did your day end that day on 9/11? do you remember what time you got back to washington or what time the day ended? >> guest: we ended up flying into washington very late in the afternoon. we, the president got aboard marine win and landed on the south lawn. the rest of the staff including me were in vans that headed to white house. by the time i caught up with president he was down in the peoc, presidential emergency operations center