After failing to secure last minute train tickets to Baotou, Inner Mongolia, I was recommended by a friend to call the Ctrip travel agency to see if they perhaps had any plane tickets left. Literally last minute (I called them at 2 am the morning that I was hoping to leave), I was very surprised to find that they indeed still had tickets from Beijing to Baotou (albeit out of Nanyuan airport) at the regular price (~RMB 650 with taxes included). They were very cordial about it and let us pick up our tickets literally around 2 hours before the flight at one of their outposts near the Dongsishitiao Subway station. Once we arrived Nanyuan airport, we were again greeted by a very helpful Ctrip agent who assisted us with the checking-in process.

Overall, definitely recommend using the Ctrip service for travel.