Two falling objects, regardless of mass, will not necessarily fall at the exact same velocity. In the absence of air resistance, all objects accelerate due to gravity at approximately 9.8 meters per second squared. However, air resistance, or drag, causes velocity to vary based on size, shape, and other factors.
Air resistance affects smaller objects with a large surface area relative to their mass more than larger objects. For example, a feather falls slower than a bowling ball. The drag force is proportional to surface area and airflow velocity.
In real-world conditions, gravity and drag combine to produce a lower observed acceleration. An object reaches terminal velocity when drag balances gravitational force.
In Galileo's famous experiment, objects of different masses dropped from the Leaning Tower of Pisa reached the ground at roughly the same time, though the heavier object arrived slightly faster due to a combination of mass, shape, and air resistance.
Therefore, objects fall at the same velocity only in a theoretical vacuum. In the presence of air, drag affects velocity, causing smaller objects to fall slower than larger ones.