Or like my pal "Where's that smoke coming from?" when he was talking about a large bonfire on the ground and I thought my time was up..
I took an exchange teacher from the Chinese Peoples Republic for a flight in a Jodel from Inverness, back when BAC111s were in use. We waited while a 111 took off, trailing smoke.
Later, as I circled Urquhart Castle while she took pics, she became concerned when she realised "
we were not producing smoke".