This book is about learning to see. Specifically, it is about learning to see the rich array of colors and optical effects that occur in nature and can be seen by an informed and alert passenger in an airplane. I hope to make your travel time more exciting and also to help you learn a little bit about the optical world that surrounds us. Most naturally occurring optical displays can be seen from an airplane, and some are even best seen in the air. However, your ability to appreciate and recognize optical phenomena will be enhanced if you know where and when to look and what to expect.