Is Google.com or an airlines website the only place you are looking for lights? Try these other options. Some have fee associated, which are annotated:

Skyscanner – Looking to fly from where you live to anywhere in the world? If another person has looked for flights within the timeframe you specified, pricing will show for the locations.

Hopper App – Recently have increased recognition, this app will give you estimated costs within a particular month. You can specify even more and can watch flights as well. Hopper will recommend if a price might increase or decrease in the future, using prior trends.