Here's a video displaying all commercial air traffic in the world during a 24-hour period. Seriously, I'm moving to New York City tomorrow and seeing the flight density in this computer simulation scares me a bit. Thankfully, it's a big planet with plenty of space to fly. But then, pilot friends tell me that sometimes they get close enough to wave at each other, so maybe it's not as big as to accommodate the 7.4 billion passengers that will travel by air in 2020. [Zhaw via Dark Roasted Blend ]