I heard that Airlines do not like you shopping around for prices from someone who did this research. They log you when you first come on their site. If you come back 2-3 days later, they will jack up the price, presumably to scare you into buying tickets.
Semi-related fun fact: at least on American Airlines' Gogo service, in-flight wifi requires you to pay for each device separately and charges more for laptops than for mobile devices; but it just checks your MAC address and user agent, respectively. Have your laptop browser identify as a mobile to get the better price, or buy on your phone/tablet and then spoof its MAC address on your desktop to use both devices for the price of one.