A British Airways pilot asked Air Traffic Control mid-flight on Friday morning, "Is there any military exercises going on now?"
Airlive says a third pilot also saw the freakish lights and that the Irish Aviation Authority has filed a report with the sightings due to be "investigated under the normal confidential occurrence investigation process".
Shannon ATC replied: "There is nothing showing on either primary or secondary [radar]".
Another pilot also reported a sighting.
She added that after approaching on the left side, it "rapidly veered to the north".
The pilot described a bright light that came up along the plane before disappearing at a very high speed.
She was wondering what it could be but said it did not seem to be heading for a collision.
Several sightings of an unidentified object flying at "astronomical" speed before disappearing off the coast of Ireland has sparked an investigation by the Irish Aviation Authority. The pilot said there were "multiple objects following the same sort of trajectory", and that they were "very bright where we were".
The pilot of Virgin Airlines flight VS76 from Orlando to Manchester then reported seeing a similar thing, the website reports.
A British Airways pilot contacted Shannon Air Traffic Control saying they saw a bright light alongside the aircraft before speeding away.
The British Airways flight first reporting the unusual sighting was passing over Kerry at the time with the other flights thought to be somewhere along the south-west coast.
These comments come months after several similarly odd sightings across Ireland purporting to be evidence of UFOs.