Most of us don't choose the airline we fly so much as we choose the most convenient and affordable flight, but if you're planning to travel around the US and wanted to know what your odds are of flying comfortably on JetBlue, United, Southwest, or heaven forbid, Spirit, are, this legroom GIF shows you at a glance.
While legroom is always nice (especially for tall people), personally I'd be interested in a GIF that shows seat width as well, since that's another always-shrinking aspect of air travel that I have a vested interest in. Of course, these numbers are averaged across coach/economy seats, and don't account for spots like exit row seating, "premium" economy, or upgraded cabins where more legroom (and width) come with the territory -- and the higher price tag. CNN, who created the image, using data from SeatGuru, explains:
Measurements are for the smallest configuration offered on two common, comparable single-aisle aircraft: the Airbus A320 and Boeing 737. All numbers for economy class seats.
Also worth remembering that exactly how much legroom you personally will get on your next flight has to do with the model of aircraft you'll fly on. Make sure to check out a site like SeatGuru before you book so you have an idea what you're in for.