There are a few tips on how to avoid that, "Oh, dang it!" feeling that sometimes hits halfway back on the trip home. It starts with keeping a list of possibilities. If you use a smart phone to keep notes, set up a file of key words that will jog your memory — as in "portable collision avoidance" followed by the name of a manufacturer or two. If you're low-tech, write them down on a pad of paper. You should also include events, seminars, air-show performances or personal appearances by some of your heroes, specific aircraft you know you'd like to see, and so on.