In flight, imbalanced weight to the front of the airplane might make it challenging to keep its nose up. If the weight is overloaded to the back, the pilot might have difficulty recovering from a stall.

If an aircraft is not properly balanced (i.e., its Center of Gravity or CG is outside limits), it can lead to catastrophic flight instability. If the plane is "Nose-Heavy" (CG too far forward), the pilot may not have enough "elevator" power to pull the nose up for takeoff or landing, leading to a runway overrun or a hard landing. If the plane is "Tail-Heavy" (CG too far aft), it becomes extremely unstable and prone to an unrecoverable stall, as the nose may pitch up uncontrollably. Imbalance also forces the flight controls to work harder to maintain level flight, creating excessive drag which significantly increases fuel consumption and reduces the plane's range. This is why ground crews carefully calculate the "Weight and Balance" manifest before every flight, and why flight attendants may occasionally ask passengers to move to different seats in a sparsely populated cabin to ensure the aircraft's "teeter-totter" balance remains within safe operational parameters.