I like skiplagged's price graph, which I didn't realize until now kayak has too. Skiplagged shows it in the search result, while kayak shows it only on the front page.
I'll miss hipmunk's time chart when trying to plan flights.
Yea, I do wish Kayak had this,
on the search page (although they do have a color-coded grid illustrating how prices change if you adjusted your dates +-3 days).
I'll miss hipmunk's time chart when trying to plan flights.