The United States of America declared independence from Great Britain on July 04, 1776 and became recognized as an independent nation state following the Treaty of Paris in 1783. Since then the country has grown from 13 colonies to 50 states plus 1 district. Today the USA is the world's third largest country in size after Russia and Canada. It is governed as a constitutional republic and commands the world's most powerful and technologically advanced military.
The USA rose to military dominance largely as a consequence of being drawn into World War Two ( 1939-1945 ). Prior to becoming directly involved in the war, the USA began research and development on weapons systems for export to Britain. Air superiority became a major objective and from those efforts came significant aeronautical improvements. By the end of the war, more planes than ever before were in the skies, all of them capable flying faster and higher than their predecessors. Yet those improvements still could not match the performance of what were then being called foo-fighters, unidentified metallic spheres or balls of light that could easily outmaneuver any aircraft of the period.
Curiously, reports of foo-fighters originated largely over areas of conflict such as the European and Pacific Theaters rather than over the continental USA. However on February 25, 1942, at the onset of American involvement in World War Two, a large UFO appeared over Los Angeles. Presuming it to have been an enemy airship, it was fired upon by antiaircraft guns. The object remained in sight for over twenty minutes and was hit numerous times without any effect. Eventually it flew away over Long Beach and turned south over Santa Monica. Then it receded from view, apparently undamaged. The event also included the sighting of several highly maneuverable red lights resembling foo-fighters.
Unexplainable UFO reports in the USA prior to World War Two are rare. During 1896 and 1897 there were about 1000 reports of mystery airships. Most reports came from the western states, mainly California. Nearly all can be explained as zeppelins, balloons or meteors. However a very few were reported to have moved too fast for any machine of the day, yet too slow or maneuverable for a meteor, and were observed in weather that would have grounded any type of dirigible.
Following World War Two the frequency of UFO reports over the USA increased dramatically and in 1947 received national attention when Kenneth Arnold, a private pilot and businessman reported seeing nine unusual flying objects in the vicinity of Mt. Rainier Washington. On September 23, 1947, Lieutenant General Twining authored a secret memorandum in response to an Air Intelligence request for further information about flying disks. Twining wrote that "The phenomenon reported is something real and not visionary or fictitious." He went on to state that, "The reported operating characteristics such as extreme rates of climb, maneuverability ( particularly in roll ), and action which must be considered evasive when sighted or contacted by friendly aircraft or radar lend belief to the possibility that some of the objects are controlled either manually, automatically or remotely."
On January 22, 1948 the USAF began it's first official UFO investigative program called Project Sign. The conclusion of this investigation was that flying saucers are interplanetary spacecraft. USAF investigations continued through several more projects spanning over 20 years, ending with Project Blue Book in 1969. Since then UFO sightings over the USA have continued into the present day. They have been explored mostly by civilian UFO interest groups and to a lesser extent, weak documentary productions and alternative media such as talk radio and the Internet. There is no doubt that most military and security agencies of the USA have participated in gathering and analyzing UFO related information and that the best evidence is being kept from the general public. Several attempts to legally force the disclosure of UFO information under the FOIA have been consistently blocked by FOIA exemptions, and consequently have yielded no substantial information.