In October 2015, a US military surveillance blimp snapped free of its moorings and <a href="https://www.yahoo.com/entertainment/s/us-fighters-pursuit-runaway-blimp-195613454.html">created chaos across rural Pennsylvania</a>. The Air Force scrambled two F-16 fighter jets to monitor the runaway balloon after it shot up to about 4,600 metres in altitude, before returning to Earth, where it dragged its 2-kilometre-long tethering cable across fields and farmlands, striking power cables and causing blackouts. The story gained brief international attention, with observers poking fun at the Pentagon for letting a very high-tech balloon break free and do some very low-tech damage. I was working in the Pentagon as a defence reporter at the time and remember the quirky story as providing a moment of levity – sorry – when our attention was otherwise mainly focused on ISIS in Iraq and Syria. The tale of the rogue blimp faded quickly from the headlines after the military recaptured it without too much damage being done. I thought the same thing would happen after the Pentagon shot down what it said was a Chinese spy balloon that had been snooping over the American heartland and peering into US military bases. Beijing, which claims the balloon was a weather station, has denied any surveillance activity and went on to accuse the US of sending its own “high-altitude balloons” over China. The US, in turn, <a href="https://www.thenationalnews.com/world/us-news/2023/02/13/ufos-shot-down-but-white-house-says-no-indication-of-aliens/">sharply denied those claims</a>, though it has used surveillance balloons for decades. Surely the latest balloon story would drop from the headlines, I assumed, chalked up as an intriguing episode between the world’s two largest economies. But then things got weird. The shoot-down of the Chinese balloon off <a href="https://www.thenationalnews.com/world/us-news/2023/02/07/chinese-spy-balloon-recovery/" target="_blank">South Carolina on February 4</a> turned out to be only the start of a bizarre story. Within days, the Pentagon scrambled fighter jets on three other occasions to intercept what it referred to as “objects” that were spotted in the skies over North America – two in the US and one in Canada. Each time, the vessel was shot down. And each time, the Pentagon was unable to describe what the craft had been, though defence officials said they were "cylindrical" or "octagonal", but not balloons. Then on Sunday, Air Force Gen Glen VanHerck, head of North American Aerospace Defence Command (Norad) and Northern Command, was asked if the objects were extraterrestrial in origin. Instead of laughing off the question, he said he would “let the intel community and the counter-intelligence community figure that out”. “I haven't ruled out anything at this point," Gen VanHerck said, noting that the craft could not be categorised as balloons. Predictably, the internet went berserk with<a href="https://www.thenationalnews.com/world/2023/02/13/what-are-the-ufos-shot-down-over-north-america/" target="_blank"> rumours of alien UFOs.</a> On Monday, White House Press Secretary Karine Jean-Pierre started her daily briefing with this memorable line: “There is no indication of aliens or extraterrestrial activity with these recent takedowns.” Her statement drew derisive chuckles from journalists, but at the end of the briefing, White House National Security Council spokesman John Kirby reiterated the message, telling America not to freak out. "I don’t think the American people need to worry about aliens with respect to these craft. Period,” Mr Kirby said. But he was unable to say how the objects remained airborne, noting they had no obvious propulsion or manoeuvring systems. Mr Kirby said the fighters that intercepted the unidentified objects whizzed by at hundreds of kilometres per hour, passing, "in terms of relative motion, a stationary object that was not very big". The Pentagon had previously described one of the objects as about the size of a small car. The strange events have underscored how <a href="https://www.thenationalnews.com/world/the-americas/us-intelligence-ufo-sightings-cannot-be-explained-1.1248889">unidentified aerial phenomena</a> are now a matter of serious Pentagon study. President Joe Biden started receiving intelligence briefings on the issue in June 2021, Mr Kirby said, the same year that a <a href="https://www.thenationalnews.com/world/the-americas/us-government-finds-no-evidence-aerial-sightings-were-alien-spacecraft-1.1235234">government report documented more than 140 cases </a>of unidentified aerial phenomena, or UAPs, that US military pilots had observed since 2004. And Mr Biden on Monday directed an interagency team to study the "broader policy implications" of UFOs. The Pentagon says it won't know more for sure until it can recover debris from the craft, scattered across frozen and remote terrain in North America. It's a process that could take days or weeks as recovery crews grapple with frigid winter conditions. Many Americans are already deeply suspicious of the US government and are quick to see conspiracies around every corner. I suspect we will eventually be offered a rather mundane explanation, but until the US provides answers, speculation will only grow as to what these vessels were.