I even have seen it with my own eyes. So there is something going on..
Your eyes don't deceive you - you are absolutely correct. A friend of mine's ex-girlfriend once went out with a Pilot, and she said that he said that they turn off the air for take-off and landing to save fuel and so that the cabin crew don't get asked for all those drinks. I flew to Majorca two years ago and feel asleep almost as soon as the door was closed on my flight home which proves it - I've heard that the Russian and Turkish airlines are the worst, and that the crew steal stuff from you when you are asleep!