Drag

$F_{x} = \frac{1}{2} ρ V^{2} S C_{x}$

$C_{x}$ : Drag coefficient depending on the airfoil and incidence
$ρ$ : Air density
$S$ : Wing area
$V^{2}$ : Speed squared of the aircraft

This is the forward drag. It is parallel to the relative wind, and is made up of 3 drags:

Form drag**: resulting from the volume of air displaced by the aircraft.
Frictional drag**: resulting from the deceleration of the air near the wing's Skin.
Induced drag**: due to the Lift.

This induced drag will create vortices at the trailing edge: the Marginal Vortices. There are also vortices created all along the trailing edge: the free vortices.

To reduce the induced drag, one can :

Increase the Stretch.
Add Winglets.
Add Wingtips.

Drag

META