There's a comfortable bar and cafeteria-style restaurant on the upper level-- maybe the one LondonElite is referring to? It does feature some german food but nothing special. Other than that I don't remember any comfortable indoor space to relax.

The outdoor observation deck on the other hand is great if the weather is dry. Excellent views of both runways and the ramp.

Both are outside security but re-entering the secure side is quick and efficient.