Aircraft are vehicles which are able to fly by gaining support from the air, or in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Although rockets and missiles also travel through the atmosphere, most are not considered aircraft because they do not have wings and rely on rocket thrust as the primary means of lift.
The human activity which surrounds aircraft is called aviation. Manned aircraft are flown by an onboard pilot. Unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, propulsion, usage and others.
On July 17, 1962 the US Air Force Major flew his X-15 rocket plane to an altitude of 59 miles (95km) above the Earth and reached weightlessness. He could see the coastline of the Western United States from north of San Francisco down to Mexico By that time four Americans had gone into space but they were in capsules that splash landed under parachutes in the ocean. White successfully flew his plane back to Earth and landed it on a dry lake bed at Edwards Air Force Base in California.
One approach to manned space flight is to put a man in a rocket and depend on a parachute or other drag-making device to ease him back to earth. Another approach is to fit a piloted airplane with rocket motors powerful enough to toss it out of the atmosphere. It will have wings of a sort for gliding, and the pilot will land it like a conventional but extra-hot airplane. The X-15 rocket-plane built by North American Aviation, Inc. is the second approach. It will probably make its first flight to the edge of space in less than a year. Made of stainless steel to resist heat, it is a stubby-winged airplane only 50 ft. long, weighing about 33,000 when fully fueled. Its single rocket engine has 60,000 of thrust and is capable of lifting it off the ground like a ballistic missile.
The rocket engine will have fuel for only six minutes of powered flight, but after its fuel is gone, the X-15 is expected to climb on momentum at least 100 miles above the earth, probably a good deal higher. This altitude is not strictly space; there is still a little air, but it is much too thin for an airplane to steer by. So for controls the X-15 will use six small jets of hydrogen peroxide gases shooting out of its tail and wings. When the X-15 is above the effective atmosphere, its pilot will feel zero gravity and float off his seat to the limit of his belts. Loose objects in the cockpit, if any, will drift around like smoke. This condition will last for something like five minutes, ending only when the X-15 meets denser air on the way down.