We use www.itasoftware.com ................. MOST of the time they have the cheapest airfares listed .............. but ALL the time they have the best features to find specific dates, range of dates, length of stay, etc.. search results and a ready to read calender of results ..................... we use these features to find the best days to travel, best time of travel, etc.......... THEN go to airline sites, discounters etc..... to find the actual best prices .................... MOST of the time the airline websites themselves have the best deals