I am US Gold and counting and fly CO to IAH from MCI. Last Wednesday, the fare for a flight I needed in 4.5 weeks was $250 on one of the little jets. On Monday, it was $649 4 weeks out. This is a typical experience I have seen on CO--I prefer CO to stay within *A, but am about to consider AA over this (I also fly to LAX and ORD) so that I don't break my work budget! What gives with these rate increases that can literally go up $400 overnight well in advance?