It was very interesting. At the United check in counter at Frankfurt, they had about 5 or 6 well-dressed, professional, burly American security agents interviewing the passengers. The guy introduced himself, explained that he was with a firm from Los Angeles, and proceeded to question me for several minutes.
He asked where I was from, what I was doing in Germany, when did I plan my trip, what I did back home (work, etc), my age, where and who I was with in Germany, who had brought me to the airport (my German friend, who was standing a few meters away), where my friend lived, what my friend did for work, the contents of my suitcase, exactly where the suitcase had been for the past few days, etc, etc.
The agent didn't go very far with me. I was freshly 18 at the time and it was obvious that I was just visiting my friend and his family in Germany for the holidays. But I observed that other people were really grilled by the agents.
I'm not sure whether this is commonplace at Frankfurt. I've not experienced it elsewhere in Germany or Europe. I wonder whether United had received threats on that particular flight, but it seems unlikely, as the whole interview process was really well administered (didn't seem hasty at all).
This was prior to 9/11. Whatever the reason, I think it was great that United went to such extreme, well-organized security measures.
This is the time. And this is the record of the time.