When you travel frequently (and definitely when you work in travel), you get familiar with airport codes. Some airport codes are pretty obvious, like ATL for Atlanta. Some of them definitely aren't, like YYZ for Toronto. Have you ever wondered what they mean? Here's a quick airport code lesson for you. Airport codes have been around for nearly a century and every airport in the world gets one as a unique identifier. Actually, every airport in the world gets two - a four c