Flight Penguin

Great way to track down the cheapest flights especially if you are flexible on departure and takeoff window.

The only search engine that can pull in Southwest and Frontier too. Can order by travel time and how many stops. I use for every flight I even think about buying.

I clicked add to Safari (because I use Safari) and it flipped me over to Chrome. Looks like there isn't a Safari option anymore. Fine. Edit the site then!

So happy to see Flight Penguin after losing hipmunk - awesome feature set, makes booking civilized flight times so easy