Weight
Weight(w) is the force of gravity pulling the plane towards the center of the earth, and is a product of gravity (g) and mass (m). The magnitude of a plane's weight is dependent on the mass of the entire aircraft, including the mass of the fuselage, the passengers, fuel and the luggage. To calculate a plane's total weight you add the weight of all the components of a plane together as seen in figure 1. To calculate the weight of the indivual components , the formula w=mg is used, where w is weight, m is mass and g is the gravitational constant which is 9.8 m/s^2 on earth. Whilst in flight a plane rotates around the average location of the weight of an object. This point is known as the center of gravity. To fly a plane must overcome it weight by generating lift. The video below explains how weight interacts with the other aerodynamic forces to achieve flight. The following link further explains weight if you require further explanation https://www.grc.nasa.gov/www/k-12/airplane/weight2.html