I've used Google Flights before, but I almost always end up flying Southwest, which doesn't disclose their prices to aggregators. Does anyone know if Google has tried to strike a deal with them? If anyone could, I imagine it would be Google.
Here is their terms of service:
https://www.southwest.com/html/about-southwest/terms-and-con...
They explicitly take ownership of the content, mention that the information is only for non-commercial use, exclude use of the information on their site for commercial use and additionally use for any other purpose. In case their message is not clear, they go even further and list a variety of prohibited activities.
The language of their Terms & Conditions is rather broad. It looks like virtually any activity on their website as a violation. Perhaps that is now the norm.
Until one of these sites includes all airlines, I'll remain relatively unimpressed with anything new that comes out.