The four aerodynamic forces are thrust, drag, lift, and weight.

These aerodynamic forces work together for controlled flight.  Thrust is the force needed to move the aircraft forward, overcoming drag.  Drag is the force that keeps an aircraft from moving forward.  Lift is the force that opposes weight and keeps the aircraft flying.  Weight is the mass of the aircraft that is affected by gravity.

Reference(s):

FAA-H-8083-21A – Helicopter Flying Handbook pg. 2.2

Other Helicopter Aerodynamic Principles