I, for one, would like to see a network of skywatch stations established at strategic locations throughout the world. Flying aircraft of various types have certain characteristics that distinguish them and allow for identification as aircraft. All conventional aircraft depend on aerodynamics, a branch of fluid mechanics that deals with the motion of air other gaseous fluids, and with forces acting on bodies in motion relative to such fluids. Aircraft move through air in a fairly uniform linear path at a fairly uniform speed until they turn, dive, or roll as they do in airshows. One of the fundamental forces studied in aerodynamics is lift, or the force that keeps an airplane in the air.
Airplanes fly because they push air down.
The leading edge of an airplane wing is higher than the trailing edge. All aircraft have wings or lifting bodies or rotating blades as their lift depends on them. UFOs may not have wings and may even have some unaerodynamic configuration. The air pressure on the upper side of an airplane wing is lower than that on the lower side giving a resultant net force upward. Another important aspect of aerodynamics is the drag, or resistance, acting on solid bodies moving through air.