How does mass affect an objects inertia?
A massive object has greater inertia. It requires more force to slow it down or change it's course. Example: It takes much more force to stop a train than it does to stop a car, only because the train has much greater mass.
momentum is caused by inertia. all objects have inertia, which means if they are moving at a certain velocity or are at rest they will continue to move at that velocity or remain at rest unless acted on by a force. Objects of more mass have greater inertia, so the amount of momentum is equal to the product of an objects mass and the magnitude of its velocity.
Since the weight of an object is variable in different gravitational environments, and mass is the same in any environment, it would be more appropriate to ask whether less massive objects have less inertia than more massive objects. Since inertia is a measure of mass, the question answers itself. More massive objects have more inertia. In any given gravitational environment, more massive objects also weigh more.