The big transport plane flew out of a cloud just as the sun appeared over the flat horizon of the desert to the east. The rolling hills over which the clouds hung low smoothed out as they met and merged with the flat wasteland. A row of trees, the only ones in sight, lined one edge of a rectangle even flatter and smoother than the land near by. A long, low building near the trees, with two small airplanes in front of it, identified the rectangle as an airfield. Before the transport reached the field, another slid out of the cloud. Suddenly swift fighter planes darted past them, swept low over the airfield with machine guns splattering their bullets over the hard earth, the two small planes, and the low hangar. They circled swiftly, just as a third transport appeared from the clouds, and roared past the field, on the far side of the line of trees. Long streaks of white smoke poured from them, falling lazily and billowing into man-made clouds as dense as those in which the planes had recently been flying. In five minutes the smoke screen was a wall twenty feet thick and a hundred feet high.