A board sitting on the beach not moving and not attached to a rig can achieve lift off the ground if there is enough wind. Lift from air moving under the board is REAL I have seen too many boards moving down the beach in big gusts. I am always careful how I set mine down when not attached to the rig.
Yes, the fin does bend in the transition from reach to a higher point of sail, and it does contribute to the lift, but the key is air moving under the board. Remember, the board speed is dropping as the board turns upwind, but the apparent wind is increasing.
Chop hopping is essentially the same, air moving under the board as the board moves into the air with significant apparent wind. You only need a small wave to create a space for the air to move under the board and bingo - LIFT. It's not just the speed of the board over a ramp, although this plays a big role in getting air.
You get bigger jumps when the wind increases, but the board speed and chop size remain the same.
Formula 160; iSonic 111; HiFly Move 105; Tiga 263; '85 Mistral Superlight.
Maui Sails TR 11.0; 9.2; 8.4; 7.6; 6.6; Maui Sails Switch 6.0; 5.2; Maui Sails Global 4.5; 4.0.