How does an increase in weight affect aircraft takeoff?

An increase in weight requires increased thrust and results in a longer takeoff distance because the aircraft needs to generate greater lift for a heavier mass. During takeoff, lift is generated through the aircraft's speed and angle of attack. When an aircraft is heavier, it has a higher stall speed, meaning it must reach a higher speed to produce enough lift to become airborne. Consequently, the engines must provide more thrust to achieve this necessary speed before the aircraft can take off. This extended requirement for speed translates to a longer takeoff roll on the runway.

In contrast, a lighter aircraft requires less lift and, therefore, can take off sooner and over a shorter distance, as it reaches the needed speed for lift-off more quickly.