What are the areas of vulnerability in air cargo transfer?

There are many areas of vulnerability in air cargo transfer—some of them are common to all types of cargo transport, but some are specific to air travel. In any sort of cargo transport, there will be issues with items shifting during travel, customs and international law, and similar issues. International transport can be problematic because there are many areas that are difficult to inspect in fine detail, and so unregistered items can be smuggled in, or things can be rejected for simple reasons. Additionally, damage can happen during transport, like mentioned before.
With air travel specifically, however, you run into several other issues—air pressure changes, temperature changes, and limited space. These can make air transport particularly vulnerable. For instance, because of the air pressure changes, lithium-ion batteries cannot be shipped via air delivery, because they may detonate. Temperature changes can damage sensitive goods, and limited space means a potential for crushing, shifting, or other damage, as well as simply being unable to transport larger or heavier items.