Unlike fixed-wing aircraft, the helicopter's main airfoil is the rotating blade assembly (rotor) mounted atop its fuselage on a hinged shaft (mast) connected with the vehicle's engine and flight controls. In comparison to airplanes, the tail of a helicopter is somewhat elongated and the rudder smaller; the tail is fitted with a small antitorque rotor (tail rotor). The landing gear sometimes consists of a pair of skids rather than wheel assemblies.

The fact that the helicopter obtains its lifting power by means of a rotating airfoil (the rotor) greatly complicates the factors affecting its flight, for not only does the rotor turn but it also moves up and down in a flapping motion and is affected by the horizontal or vertical movement of the helicopter itself. Unlike the usual aircraft airfoils, helicopter rotor airfoils are usually symmetrical. The chord line of a rotor, like the chord line of a wing, is an imaginary line drawn from the leading edge to the trailing edge of the airfoil. ...more

Excellent exposition by Mr Kartikeyan

HELICOPTER IS LIGHT WEIGHT CAN CARYY FOUR OR FIVE WITH PILOT AND HAVING A STRONG FAN UP IT CAN LAND SAME AREA VERTICALLY AND FLY VERTICALLY. BUT AN AROPLANE IS LONGER IN SIZE AND CARRY ATLEAT A SAMLL AIRCRAFT OF DC TEN CAN CARRY 33 PROPE SO IT IS WEHTED CAN ONLY FLAY VERTICALLY AND LANDING TOO. mUCH FORCE IS REQUIRED IN BOTH THE PROCESSES.

It is all about lift of mass. Huge fan blades are used in case of chopper to execute the lift, which is not the case for Aircrafts having comparatively large masses.