So while you are napping, eating or watching a movie on that flight to LAX, you should know the plane you are flying is cruising along at the ratty edge of its capabilities. Why? Money. The higher an airliner flies, the better gas mileage it gets.

But rest easy, white-knucklers; flying in the “Corner” is routine and safe - so long as the weather is benign, the air is smooth and the sensors, avionics, computers and autopilot are all doing their job.

But of course that was not the case for Air France 447.