Originally Posted by fransknorge

To join the S Bahn station Flughafen Bf from DUS airport, you need to take a Skytrain, a small monorail linking the airport to the station, it is frequent (every 5 minutes) and takes 5 minutes. It is not a free shuttle.Be aware you need a ticket for that, and it is highly possible your train ticket does not include the sky train.
Right now the biggest unknown are baggage delivery, they tend to be longer than usual. If you take a flexpreis then do not worry.