Can anyone tell me how the dragon "aims" a trip from the Astral to the Material? Or vice versa, I guess, if the main campaign activity is happening on the Astral. I don't have the Manual of the Planes and I don't see anything applicable in the DMG, PHB or Planar Handbook. If it's like astral caravan, the dragon would pick a destination and arrive 10-1000 miles away, making the ability not useful for anything except Getting The Hell Outta Dodge.