the window of a moving car?
Most of the time your hand is pushed backward. In order to achieve lift you must angle and shape your hand that does imitate an airplane wing.
The large lift force you are feeling is due to the flat palm of the hand facing the air-flow at a angle to the horizontal. In this position the hand surface is colliding with air particles and defecting them downwards the hand is exerting a downward force on the particles and you feel the reaction force from the particles acting in the upwards direction. Most of the lift force generated by an aircraft wing during take-off ( with fuselage at a greater angle than the actual climbing angle) is generated in this way. Force acting on downward deflected air F downward rate of change of air momentum F ?(mv)/t (m/t)?v m/t mass of air deflected per sec with velocity change ?v Upward lift (reaction) force -F
