Had you never tried hipmunk before this?
It's especially good if you want to do an open-ended search, as in you know where you are leaving from and which month you might want to leave, but you're flexible as to where you want to go.
It happened to mortgage rates companies, it happened to flights, and eventually given enough it'll happen to any service that acts as a broker/affiliate for other companies.
which means on the back end much lower traffic for the companies, which in turn drives down the rates you can charge for the leads.
Or buy you. The trick is to be so good at what you do that it's easier for Google to fork out cash than engineering resources.
This is what antitrust laws are for.
Google has a lot more in terms of schedules.
They also don't have mascot, or hotel search ;)
I'll leave it there.
Flights to an airport http://www.google.com/search?q=flights+to+SFO
Change SFO to airport code of your choice.
If it could plot non-nonstop routes and quote me prices for specific days, then it'd be really disruptive. But as it is, if I want to go somewhere surely I'll take the extra few seconds to check a proper travel site?