We were taught in school that aeroplanes fly because the wings are bulbous on top, so the air has further to travel, therefore does it faster, therefore at a lower pressure, so developing lift. I heard this explanation given by a teacher to a class at an 'hands on' demonstration in the Science Museum with an expanded polystyrene wing and a hair dryer - shure enough the wing convincingly shot upward when inserted in the air flow. After they had gone I tried it myself, and it became clear to me that the convincing lift came not from the Bernoulli effect but from the angle of attack - held level there was no detectable lift; the children were being conned.

And in any case, aeroplanes can fly upside down, can't they?

So for a Jumbo at cruising altitude in level flight what proportion of the lift is due to the angle of attack, and what proportion to the hump in the aerofoil?