A spectacular and unusual cloud formation has been photographed in the skies above Australia from a passenger jet.
Ilya Katsman was on board a Virgin flight from Perth to Adelaide when he snapped the long, white parallel tubes of clouds above the sea.
"The most unique cloud formation I have seen to date," he wrote on Instagram.
Known in Australia as 'Morning Glory' or ' kangólgi' clouds, it's believed they're formed through a combination of breezes, and air rising, freezing, cooling and rising again. Their rarity makes them difficult to study.
They're most common in the country's north, but have been known to pop up as far south as Tasmania and even occasionally New Zealand.
They're usually about 100m across, but can stretch up to 1000km.
"There are fewer people who have flown on the Morning Glory than have climbed Mount Everest," cloud-chaser Garrett Russell of the Caboolture Gliding Club in Queensland, told news.com.au.
Virgin Australia posted the photos to its Facebook page, where many viewers accused the company of spraying the air with 'chemtrails'.
"Those are no natural clouds," wrote Daniel Clark. "The result of chemtrails with wave frequencies being transmitted through them from the closest haarp stations."
Conspiracy theorists believe chemtrails are sprayed by planes at high altitudes for sinister purposes. There is no evidence this is remotely true.
HAARP, the High Frequency Active Auroral Research Program, was a US scientific programme to study the upper atmosphere with a view to improving radio communications.