IS IT a bird, is it a plane? Wait a second ...

Something very strange has been happening in Australia’s skies, baffling even the nation’s top air safety experts.

It turns out that pilots have been reporting sightings of mysterious flying objects for years, but these cases have been kept hush-hush. It’s only now that they are finally coming to light.

And it’s all thanks to two curious scientists: Paul Dean, a Melbourne-based UFO researcher, and Keith Basterfield, the author of UFOs: the Image Hypothesis.

The duo were fascinated by an Australian Transport Safety Bureau (ATSB) report into an incident near Perth on March 19 last year involving a flying object, so they delved into the case, and in the process discovered evidence of other similar encounters in Australia that had been kept a secret.

The ATSB report had concluded that an unmanned aerial vehicle (UAV — otherwise known as a drone) may have been responsible for the March 19 sighting.

But there are doubts, with an ATSB spokesman telling news.com.au: “The ATSB was not able to confirm the details of the object or identify any UAV operator in the area at that time.”

Details of the incident were provided in the report: “At about 3800 ft above mean sea level, the crew sighted a bright strobe light directly in front of the aircraft. The light appeared to track towards the aircraft and the crew realised that the light was on an unknown object, possibly an unmanned aerial vehicle (UAV) ...

“The pilot reported that the object was cylindrical in shape and grey in colour.”

The shocked pilot, who had 53 passengers on board, was forced to take evasive action to avoid a collision with the object.

Dean and Basterfield had originally pushed for the case to be classed as a UFO event. However, they have just published a new analysis of the close encounter, and now they believe that someone could be firing rockets at planes, Crikey reports.

Why did they change their minds? The scientists had lodged a freedom of information request with Air Services Australia, asking for information on recent cases of unexplained objects in our skies. They were stunned when the response to their request detailed 13 incidents over the past seven years.

One of these involved a “missile-like object” that was seen dropping in the skies, with a parachute.

According to the Airservices Australia response: “(Flight) XKI (DH8C) reported a foreign object of approximate size (1 metre) within close proximity (50ft) of the aircraft causing them to level out briefly as the object passed left hand side. The rocket like object (shaft) was observed to be attached to a parachute. Pilot reported observation at 6800 ft.”

Other strange cases include once that occurred last January, where a pilot spotted “something hovering ... which then disappeared”, and another in September 2012 where “TGW581 reported a red cylindrical object passing the aircraft in the opposite direction when climbing through FL200 approximately 20nm miles south of Sydney.”.

Perhaps even stranger was this account on April 25, 2010 near Mt Jerrabomberra, NSW: “Unidentified (upside down pyramid shaped) object drifting close to final rwy 35 ... Initially drifted west, towards final for rwy 35, before climbing and drifting to the Northeast. Two aircraft (QFA814 and VOZ259) were diverted through noise abatement areas to avoid the object.”

Dean and Basterfield have submitted further freedom of information requests for more details on the cases and continue to analyse the events. You can read more about their research on their website.

So were the objects rockets, or UFOs? For now, nobody is quite sure.

The ATSB declined to comment further on the issue when contacted by news.com.au. Airservices Australia has also been contacted for comment.