While searching for some peak Thanksgiving holiday travel today, we ran into a classic case of an airline not sharing it's lowest fare with all airfare search engines.  Therefore, the famous "search one and done" slogan which Kayak boasts doesn't always ring true.  Truth is, airfares oftentimes vary from site to site.  In this example, we see two searches side by side taken from screenshots at around 1:00pm ET Nov. 4, 2011.  We see Kayak giving us the lowest fare from New York to Bermuda departing Nov. 23 and returning Nov. 27 at $595 on American.  However, Priceline is also showing us that same routing and same dates with a JetBlue flight at $572.  It is always best to search at least a few different websites when searching for the best airfare.