Originally Posted by
GinFizz
It does give a price for routings starting in Dusseldorf Hbf - but that would just add a needless stop to my journey and raises the price as the train to Koeln is also an ICE train.
If you start at DUSSELDORF AIRPORT then you still need a separate ticket for the sky train from the terminal to Flughafen station
Taking these two things together, another option worth mentioning is purchasing a Sparpreis ticket.
It's going to cost like an extra 3 euros but that way, you're covered for the sky train. You may then start your trip from Duesseldorf Hbf as well (as the Sparpreis includes the +City option which is good for travel between the DUS airport station and Duesseldorf Hbf).