How high can pallets be stacked while being shipped via air, not including the base pallet?

When shipping pallets via air, it's essential to consider safety regulations and the structural integrity of the cargo. The standard height restriction for stacking pallets during aerial transport is generally established to ensure that the weight distribution and stability are maintained throughout the journey.

A height limit of 20 pallets when stacked is typically accepted because stacking them higher could lead to potential safety hazards. This limit reduces the risk of damage to the cargo, as well as enhances the safety of the crew handling the pallets. Taller stacks may not fit in the cargo area of various aircraft or might be subject to increased wind resistance during loading and unloading, leading to instability.

In contrast, limits less than 20 may not maximize the cargo space efficiently, while higher limits can lead to compromised safety. Thus, the correct answer reflects the balance between maximizing cargo space and ensuring safe handling during shipment.