HasWifi is a web-based tool to help you answer this question. And this can be done with your input.

A little more about HasWifi:

We need to be connected all the time… even if that time happens to be at 30,000 feet. We’re tired of being disappointed the plane we booked tickets for isn’t wireless internet equipped and we hope you are too. With your help, we hope to put an end to that feeling by showing which flights are wireless-internet capable — before buying your next ticket. We do this by asking flyers like you to Tell Us whether or not or last flight was internet capable.