Answer:
see the explanation below
Step-by-step explanation:
Momentum is a product of the mass of a particle and its velocity.
and also, momentum is a vector quantity; i.e. it has both magnitude and direction.
Now a plane in the air has both magnitude and velocity
When the plane lands the velocity will amount to zero although the mass is still very much intact
Now the mass* zero velocity= zero
Hence when a plane lands the momentum is zero