The two giant dual-rotor aircraft swooped low over Glasgow at around 3pm today.
They were seen as they circled the the city, and captured on video by @iainwitheyman.
Residents of Broomhill and Partick in the west end of Glasgow saw the two Chinooks circling for several minutes.
One woman said: "The windows of my house were shaking.
"When it was clear the helicopters were circling, I went outside to look and could feel the ground vibrating as they were really quite low, perhaps a few hundred feet.
"I presume it was an exercise linked to Cop26 - so is that what we're going to have to put up with for two weeks in November?"
It comes as the Ministry of Defence is undertaking a military venture: Exercise Chameleon 2-21.
However, while the MoD website lists the places which will be affected by low-flying aircraft, Glasgow is not among them.