I hope you enjoyed Germany.
It seems that the most plausible explanation is that she recognised him as a DEA agent and noticed that he spent all his time in Germany in the airport, just like she did. However I didn't notice any sign of sarcasm in her voice, she seemed to be completely emotionless when saying this.
This leads to a second possibility that she simply remembered him from the flight to Germany and it was just some small talk. However if this is the case then I have really hard time understanding the purpose of adding this scene in the first place.
Is it one of these two options or something else? What is the actual meaning of this scene?