UFOs "Unidentified Flying Object"

UFO "Unidentified Flying Object"  Does not mean it is from Outer Space.

Aircraft Tracking are Monitored throughout Earth by Radar & Satellites.

GPS Aircraft Tracking is used in both commercial and personal aircraft, and it comes along with a variety of benefits both to safety and convenience.

A device with a GPS sensor is embedded into the aircraft, and it is able to transmit real-time GPS positions of any plane to a server board located on the ground.

Currently, planes are largely Tracked by Radar on the Ground, which doesn't work over much of the World's Oceans.

Part of Air Space Security & Detection - Space-based capabilities (Satellites) help provide integral support to military, commercial, and civilian applications.

“The Unidentified Aerial Phenomena" tends to remain a Mystery, as to some Objects in the Sky are not Identified by Traditional Means.

We pretty much know our Technology Advancement for our Military Aircraft with "Stealth" Capabilities to Go Undetected by Traditional Means Ground & Satellite Identification & Tracking, Aircraft Radar to be able to detect the Air Space around them of Near & Far Objects.

Naturally there will Always Be Those who Want to Fly Undetected for a wide Assortment of Reasons. Or to Detect the Same as part of their Airspace Security Protection.

If these Objects were from Space, meaning Life Does Exist outside our Earth's Atmosphere and to explain UFOs Flying at Hypersonic Speeds

In aerodynamics, a Hypersonic speed is one that greatly exceeds the speed of sound 767.21 MPH is Mach 1

2 Mach= 1522.41 mph
3 Mach= 2283.62 mph
4 Mach= 2,889.42 mph
5 Mach= 3,507.22 mph

Mach 15 = about 11,418 MPH

The United States Fastest Aircraft is the Lockheed SR-71 Blackbird, current record-holder for a manned air-breathing jet engine aircraft, which is a speed of 2,190 mph.

Obviously with Friction as a Factor - the resistance that one surface or object encounters when moving over another.  Would equate to that of Air friction, or air drag, is an example of fluid friction. 

Friction is a force, the resistance of motion when one object rubs against another.

Surface friction forces are velocity dependent, the surface of that Air Craft to withstand that friction and heat build-up at speeds greater 2,190 mph as a base-line set by the SR-71.

The Space Shuttle you may remember - can accelerate at Launch from Zero to 8,000 meters per second (almost 18,000 miles per hour) in eight and a half minutes. 

Re-Entry Speeds: of typical low earth orbit are near 17,500 mph and that Mach number is nearly Mach 25.

So for UFO's from Outer-Space, from that of another Planet, Alien Life from afar...their technology to be able to travel through Space of however many Light-Years..

A Light Year is about 6 trillion miles 5,878,625,370,000 miles and to travel at 670,616,629 mph = 8,766 Hours of travel.

So Alien's as we see in Movies, would have to be very close, to travel a shorter distance in time at great speeds and to enter Earths Gravitational Pull and not Burn Up or Explode, would have to know in advance if/of their Air/Space Craft could withstand flying in and around Earth's Atmosphere to be Spotted by Humans on the Ground, or in the Air Flying, and to have gone Undetected Entering Earth.  Or even getting close to Earth in Space.

As Scientist Track Meteoroids coming and these Meteoroids moving through Earth's orbital space average about 45,000 mph.

UFO's being spotted by Jet Passenger Pilots or Military Jet Aircraft, would be detected before hand.  

However, one needs to ponder that UFO's  might have come from here on Earth, not Space.