Just so you know:

Wednesday evening (Dec. 30) the FareCompare.com proprietary airfare tracking system detected unusual system-wide airfare hike activity initiated by United Airlines.

Over 15,000 United city-pairs were increased by $6 and $10 roundtrip ($3 and $5 each way). The increase covered the bulk of United’s domestic route system — mainly at the $6 roundtrip level.

On New Year’s Eve, the remaining legacy airlines began to match including American, Delta/Northwest, US Airways, Continental and Alaska.

Please note: The hike did not have any effect on a variety of airfare sales in the domestic system for travel through early March. Legacy airlines also tiptoed around overlapping low cost airline routes (Southwest, JetBlue, AirTran) as the group has yet to participate in the hike.

This increase represents the 4th successful hike of 2009 compared to fifteen in 2008 and seventeen in 2007 — all since mid 2009.