The Irish Aviation Authority is investigating reports of UFOs off the south-west coast of Ireland.
It began at 06:47 on Friday when a British Airways pilot contacted Shannon air traffic control.
She wanted to know if there were military operations in the vicinity as she had seen something “moving so fast”. However air traffic control said there were none.
In 2008 the MoD released files on a series of reports across Northern Ireland over several decades.
On this occasion the BA pilot, coming from Montreal, said there was a “very bright light” and the object had come up along the left side of the aircraft before it “rapidly veered to the north”.
She was wondering what it could be but said it did not seem to be heading for a collision, the BBC reported.
A pilot on a Virgin plane joined in, suggesting it might be a meteor or another object re-entering the earth’s atmosphere.
He said there were “multiple objects following the same sort of trajectory” and that they were very bright.
The pilot said he saw “two bright lights” over to the right which climbed away at speed.
One pilot said the speed was “astronomical, it was like Mach 2”.
The Irish Aviation Authority said: “Following reports from a small number of aircraft on Friday 9 November of unusual air activity the IAA has filed a report. This report will be investigated under the normal confidential occurrence investigation process.”
A commercial pilot from Northern Ireland, who said he did not believe in aliens, told the News Letter: “Mach 2 is definitely a fighter of some sort and around Shannon, it is not Irish.
“It is definitely military of some sort or private military. At that time of the morning it would still have been dark and difficult to say what it would be, in my experience.
“It would also be very hard to tell what direction it would be flying.
“I don’t think this is anything untoward. There are a lot of official and unofficial military operations over the north Atlantic, British and Russian.”
The MoD previously released files of reports of UFOs in Northern Ireland.
In 2008 the government department released the information to the National Archives and have made 19 files available online for public viewing.
One of these files refers to separate reported sightings in Northern Ireland.
In one instance, correspondence by the Ministry of Defence refers to three reported sights of UFOs at Aldergrove in December 1989 and January 1990.
Another refers to an alleged sighting near Glenavy, also in 1989.
Officials conclude in this instance, while admitting an investigation was necessary, that due to no UFO activity being reported elsewhere in the UK, the person concerned “probably witnessed the arrival or departure of the helo’s (helicopters) at Aldergrove”.
The 19 files cover the six-year period from 1986 to 1992.
Almost 200 files will be made available by the MoD over the course of the next four years.
In 2010 an east Belfast man told of his “wonderment” at witnessing a mysterious flying object over the city’s night sky.
Richard Barr was at his mother Elaine’s Cregagh Road home watching television when a “huge orange light” attracted their attention.
Stunned by what they saw, both went into the back garden to investigate, only to discover further strange lights hovering above.
Although not far from George Best Belfast City Airport, the 29-year-old – who is a firm believer in aliens – is adamant it was not an airplane but “something unexplainable”.
“I was sitting watching TV and the first thing I saw was a huge orange light which appeared out of nowhere,” he told the News Letter.
“My first impression was that it was a plane on fire and I looked at my mother and she thought the same thing. We went outside and the orange light got smaller and smaller and disappeared.
“Four others (orange lights) then came across the sky and seemed to form a sort of a pattern. They hovered there for a while and then they disappeared.
“The third time we saw three triangular lights in the sky and my mother got the camera and recorded them.”
The episode lasted for several minutes.
Afterwards, Richard carried out his own investigation on the internet and concluded what he saw may have been a “black triangle”.
Black triangles are a class of unidentified flying objects (UFOs). There have been many alleged sightings reported across the UK and beyond. The crafts, reportedly enormous and silent, are often described as having “running lights”.
When contacted by the News Letter regarding what the alleged object may have been, a spokesman for the Ministry of Defence said: “The role of the Ministry of Defence is to defend the UK including our airspace and therefore naturally takes an interest in any unauthorised air movements. However, at this alleged height and location over an urban area, this is very much a matter for the Civil Aviation Authority (CAA).”
However, a CAA spokesman said the body had “no remit to investigate UFOs”.