So-called action cameras barely existed a decade ago; now they are a must-have for any adventure, whether it's skiing, skydiving or flying. Their small size, incredible video quality, and built-in GPSs make them perfect for sharing your flights with non-pilots. You can relive that flight to Oshkosh, or share your first solo with friends and family. To help you choose the right model, we've developed this Buyer's Guide with all the essential specs.