A short summary of the paper mentioned in another answer and another good site.
Basically planes fly because they push enough air downwards and receive an upwards lift thanks to Newton's third law.
They do so in a variety of manners, but the most significant contributions are:
- The angle of attack of the wings, which uses drag to push the air down. This is typical during take off (think of airplanes going upwards with the nose up) and landing (flaps). This is also how planes fly upside down.
- The asymmetrical shape of the wings that directs the air passing over them downwards instead of straight behind. This allows planes to fly level to the ground without having a permanent angle on the wings.
Explanations showing a wing profile without an angle of attack are incorrect. Airplane wings are attached at an angle so they push the air down, and the airfoil shape lets them do so efficiently and in a stable configuration.
This incidence means that even when the airplane is at zero degrees, the wing is still at the 5 or 10 degree angle.
-- What is the most common degree for the angle of attack in 747's, 757's, and 767's
Any object with an angle of attack in a moving fluid, such as a flat plate, a building, or the deck of a bridge, will generate an aerodynamic force (called lift) perpendicular to the flow. Airfoils are more efficient lifting shapes, able to generate more lift (up to a point), and to generate lift with less drag.
--Airfoil
Most of the lift comes from the main wing, and in fact the tail lifts down, so the main wing also has to support that.
(That's for a stability reason.)
The lift of a wing is roughly proportional to two things:
- angle of attack, and
- airspeed squared
so, the slower an airplane is flying, the more it raises the nose.
You will notice this the next time you fly.
At cruising speed, the plane is at around 300 knots (a knot is about 1.16 mile per hour), and it is pretty flat, with an angle of attack in the range of 1-2 degrees.
(At altitude, 300 knots corresponds to a much higher ground speed, due to the thinner atmosphere, but that doesn't change the lift relationship.)
When the plane is maneuvering in the approach pattern, its airspeed is more like 150 knots, half of cruise speed.
So it has to have roughly 4 times as much angle of attack, anywhere up to about 8 degrees, thus the high nose.
The maximum angle of attack is around 19 degrees, at which the wing stops working.
The crew has to stay well below that in order to have reserve lift in case they need to pull up suddenly, like if they hit a downdraft or wind shear, or if they have to turn quickly.
That beautiful photograph of the 747 was taken by another plane flying in formation with it, and for a photo shoot it was probably not travelling at cruising speed.
(It's also not very high, unless that's the Himalayas in the background.)
Best Answer
There's no problem with the Bernoulli effect, only with the way it's understood and explained. It's usually explained with mistakes, like the need for asymmetrical airfoil and equal flow time above and below, and without mentioning the need to deflect the direction of airflow.
Here's the best light-math explanation I've seen. Also study this section that directly answers your question.
EDIT: It is easy to find wrong pictures like this:
as opposed to a correct one like this (from the link above):
So the answer to your question is: All of the lift depends on the Bernoulli principle, because speed and pressure are in trade-off, but the physics need to be correctly understood.