On two occasions in five years I have ridden in a Chinese taxi at night with the headlights purposely turned off. In both cases, I complained, and in both cases the driver patiently explained to me and my fellow passengers that he was saving fuel (he wasn’t – but I’ll leave that discussion to wikipedia).

I bring this up because of an experience that I recently had on the tarmac at Guangzhou’s Baiyun International Airport. I was on Shanghai Airlines flight 9302, Guangzhou to Shanghai’s Hongqiao Airport, departing at 2:30 PM on a tropical afternoon (temperatures exceeded 38 celsius that day). As we left the gate, and taxied to the runway, the plane slowly began to heat up. This would have been no matter except that we sat on the runway for twenty minutes, awaiting clearance for take-off. As we sat, the plane continued to heat up. After five minutes, I noticed people sweating, fanning themselves, and trying to turn on those annoying overhead vents that blow concentrated air on passenger heads . After ten minutes, I paged a flight attendant and asked whether the air-conditioner was on. She answered – no surprise – that it was not. I asked that it be turned on. She said that she would tell the pilot. Of course, she didn’t – I watched as she returned to her seat beside cockpit door and muttered something to another flight attendant, who was busy fanning herself.

I don’t know anything about jet mechanics, but it seems to me that turning on the air-conditioning in a pressurized cabin probably doesn’t draw down much more fuel than what is already being consumed by idling the engines on the tarmac. Maybe I’m wrong. I don’t know. If anybody can offer some insight into this, I’d appreciate it.