The airports closest to Cologne City are the:
From Cologne Bonn Airport you can reach Cologne central station by rapid-transit railway (S13 Line) in just 15min. Düsseldorf Airport is connected to Cologne central station via rapid-transit railway (S11 Line, about 80min) or intercity railway (IC/ICE trains, about 45min). The trip from Frankfurt Airport to Cologne central station with the ICE high speed train only takes about an hour.