it definately has aired, but not to be seen.
just incase anybody wonders here is a statement from the station airing it - with all the air dates:
From Movie Central:
There was a hiatus in the programming brought to our attention by MGM. We are simply following the delivery/programming schedule provided. The new episodes will return in November 20 with the second half of the cliff hanger (The Return Part 2). Another hiatus will occur in December with the episode "Tao of Rodney" being the last episode airing on Dec.18. In January, the series will resume with "The Game" and that will air January 8 and then the series will then continue to the end of the season.
So that gives us:
Stargate Atlantis - S03E11 - The Return (Part 2) - 20-Nov-2006
Stargate Atlantis - S03E12 - Echoes - 27-Nov-2006
Stargate Atlantis - S03E13 - Irresponsible - 04-Dec-2006
Stargate Atlantis - S03E14 - Sunday - 11-Dec-2006
Stargate Atlantis - S03E15 - The Tao of McKay - 18-Dec-2006
Stargate Atlantis - S03E16 - The Game - 08-Jan-2007
Stargate Atlantis - S03E17 - The Ark - 15-Jan-2007
Stargate Atlantis - S03E18 - Submersion - 22-Jan-2007
Stargate Atlantis - S03E19 - Vengeance - 29-Jan-2007
Stargate Atlantis - S03E20 - First Strike - 05-Feb-2007