A man on the ground or even in a plane, watching the maneuvers of an object some 20,000 to 100,000 feet above him, finds it impossible to make an accurate estimate of its true height, diameter, distance, or speed. Strong windcurrents can change the orientation of the sphere, and the particular angle of vision of the observer can make the object look wholly unlike a balloon. It may assume the shape of a disk, a lens, a teardrop, a parachute, a sausage. Temperature inversions can produce a double image of a balloon so that it looks like a linked pair. Balloons released in pairs or clusters may seem to be traveling in formation under intelligent control. Sunlight, moonlight, or the lights of a city reflected from the surface may cause them to look white, gray, amber, red, silvery, or metallic. Since balloons often carry a heavy instrument load, they may give a radar return that indicates a solid object. When balloons develop a leak, they may drop some distance at high speed and then level off, as though under intelligent control. At the extreme cold of high altitudes they may burst and suddenly vanish. High in the sky at morning and evening twilight they may appear to be self-luminous, taking their light from the invisible sun just as our artificial satellites do. They often travel high above the air lanes, higher than any plane can go, where varying wind streams may propel them at great velocities, slow them until they seem to hover and be almost stationary, abruptly change the direction of their motion so that they reverse course, dive toward the earth, or ascend rapidly into the sky. At night all these illusions are magnified because the observer has fewer visible reference points by which to evaluate the true shape, distance, and type of motion of these wandering spheres. They can deceive even the most hardheaded and able pilot. The pilot is only human when he doubts that any balloon can fool him--until it does. _The Guantánamo “Dogfight”_ An American Navy pilot, practicing night flying over the Guantánamo City base in Cuba on the night of September 24, 1952, engaged in a “dogfight” with a balloon that exhibited all the characteristics associated with this type of flying saucer. It seemed to take evasive action, deliberately elude the pilot, make head-on passes, and respond to every move of the plane with a countermove.