A pilot's chilling encounter with 'alien mothership' has resurfaced, with conspiracy theorists calling it one of the greatest cover-ups in US history. 

In 1986, Captain Kenju Terauchi and his crew aboard Japan Airlines Flight 1628 reported two mysterious lights trailing their plane over Alaska. 

The objects, confirmed by both onboard and ground radar, shadowed the flight before vanishing. Then, Terauchi described the sudden appearance of a colossal craft, far larger than their Boeing 747, prompting intense speculation and debate. 

Despite Captain Terauchi's detailed testimony, FAA interviews, crew sketches of the craft, and audio recordings between the Japan Airlines Flight 1628 crew and air traffic controllers, the UFO encounter has faced decades of debunking efforts.

A high-ranking FAA official later claimed he was present when the CIA allegedly suppressed the incident, insisting Terauchi's sighting 'never happened.' 

The backlash reportedly cost Terauchi his career, as the veteran pilot was grounded after publicly discussing the event.

Recently declassified documents revealed the extent of evidence held by both Japanese and US governments regarding the UFO mothership, including radio transcripts detailing the moment the giant mothership appeared above flight 1628. 

In 2018, UFO researchers noted that these records were quietly entered into US government's National Archives decades after the 1986 UFO sighting and years after Freedom of Information Act (FOIA) requests to unseal the recordings.

Terauchi's flight from Paris to Narita International Airport near Tokyo crossed over eastern Alaska on November 17 when the 747 airliner spotted the two strange lights and enormous mothership over US airspace.

The bright yellow and white objects reportedly flew dangerously close to the aircraft, causing Terauchi to radio for air traffic controllers (ATC) in Anchorage for help.

'We see irregular pulsating lights just... there is a large black chunk just in front of us, distance is five miles... it seems to be a spaceship,' the pilot said.

'I'm picking up a hit on the radar approximately five miles in trail of your six o'clock position,' Anchorage ATC said during the 1986 sighting. 

Anchorage ATC reported spotting something on radar near the airplane and contacted the military to make sure they didn't have any planes near flight 1628. 

NORAD, the military command responsible for defending the airspace over the US and Canada, confirmed there were no military flights anywhere near Terauchi's plane that night.