I have a 100-knot airplane. Oh, sure; the airspeed indicator usually reads much higher than that. But when it comes down to what really counts-rate of movement over the ground-my shiny, expensive, 160-knot airplane is frequently relegated to speeds closer to those of an 18-wheeler on the Interstate below me. The reason? Headwinds. Eastbound, westbound-any direction-its not a matter of whether Ill have a headwind, but how strong it will be. If I plan a trip for Tuesday, on Monday the chosen route will afford a nice little nudge. On Tuesday, the fickle fates will deal a howling 40 knots on the nose. After an unplanned fuel stop, Ill drag into my destination about two hours late, landing only after being forced to shoot an ILS to near-minimums and well after the FBO has closed. The only food available will be a warm Pepsi and a package of cheese crackers. On Wednesday, that same route will once again have a nice little tailwind. Such is my life. Of course, there are good, logical reasons for headwinds. Lets explore them.