Why is it necessary to ship tennis balls on ground instead of in the air for cargo?

why by truck instead of plane? Please explain why and what would happen if shipped by air.Why is it necessary to ship tennis balls on ground instead of in the air for cargo?
i think it might be shipment by air is more expensive.





to my understanding, cargo area of cargo planes are also pressurised, though not until the comfort like in a passenger plane. as this is to reduce the chance of damage to the cargo it is carrying. else the bubble bags used in packaging will deform also.Why is it necessary to ship tennis balls on ground instead of in the air for cargo?
Tennis balls are filled with air.





At sea level, the atmosphere is pressing on the outside of the ball and against the air inside the ball. These two pressures are equalized and the tennis ball stays ';tennis ball'; sized.





At higher altitude there is less atmospheric pressure pressing on the outside of the ball, but the pressure of the air inside remains the same. Since there is less force on the outside of the ball than on the inside of the ball, the ball will expand presumably to the point of ruining the ball in some way. Perhaps it will stretch out of shape or pop. . .
im not entirely sure but i think it has to do with air pressure, if its shipped by air they would expand, I'm not sure they'd explode though
in air shipping, tennis balls will expand due to pressure change of air flight and would be damaged