Compared with ocean and railway transportation, air transportation has the advantages of fast transportation speed, high cargo quality, and being not limited by ground conditions. Cross border e-commerce breaks down bulk shipping container trade orders into high-frequency fragmented small trade orders, and more and more export goods are presented in the form of air parcels. This change has led to an overall downturn in international shipping business on the one hand, and on the other hand, it has brought significant development opportunities to the international air transportation industry, especially the logistics of the global postal system and commercial express delivery system, which are currently thriving due to cross-border e-commerce, are mostly completed through air transportation. International aviation mainly has the following modes of transportation.

（1） Flight transportation

Airline transportation refers to aircraft with fixed departure times, routes, and stopping stations. Due to the fixed route, port of call, fixed flight schedule, and relatively fixed fee standards for air transportation, it is possible for importers and exporters to anticipate the departure and arrival time of goods before signing trade contracts, calculate freight costs, and ensure the performance of contracts. Therefore, it has become the preferred form of air freight for most traders.

According to the different business objects, flight transportation can be divided into passenger flights and cargo flights. As the name suggests, the latter only undertakes the transportation of goods and mostly uses full cargo planes. Due to the limited cargo volume carried by air transportation in international trade, cargo flights are only opened by some larger specialized air freight companies or some comprehensive airlines with a wider business scope on routes with relatively concentrated cargo volume. For passenger flights, general airlines usually use mixed passenger and cargo aircraft, which also undertake the transportation of small batches of cargo while carrying passengers.

（2） Charter transportation

Charter flight transportation refers to the leasing of an entire aircraft by an airline to one or more charterers (charterers refer to shippers or air freight forwarding companies) in accordance with agreed conditions and rates, to load goods from one or several airports to a designated destination. Charter flight transportation is suitable for the transportation of bulk goods, with lower rates than regular flights, but longer delivery times than regular flights. Due to the limited cargo space in the form of flight transportation, charter flight transportation becomes an important method when there is a large amount of cargo.

The mode of charter transportation can be divided into two forms: full charter and partial charter. The so-called whole charter flight refers to the transportation method in which the airline or charter agent leases the entire aircraft to the lessee in accordance with the conditions and freight rates agreed upon by both parties in the contract, and loads goods from one or several airports to the designated destination. Partial charter refers to the form of cargo transportation in which several air freight forwarding companies or shippers jointly charter an aircraft, or charter companies sell the cabin of an aircraft to several air freight forwarding companies. Relatively speaking, some charter flights are suitable for transporting goods of more than one ton but with insufficient cargo volume for the entire machine. In this form, the freight cost of goods is lower than that of regular flights, but due to the need to wait for other shippers to prepare the goods, the transportation time is longer.

（3） Centralized consignment

Centralized consignment refers to the process in which an air freight forwarding company consolidates several batches of individually shipped goods into one batch for consignment to the airline (which can be transported by flight or charter), fills out a master waybill, and sends it to the same destination, which is then distributed to each actual consignee by its authorized local agent. The centralized freight rates of air freight forwarding companies are generally lower than those of airlines, and shippers can obtain lower rates than airlines, thereby saving costs. In addition, air freight forwarding companies consolidate the shipment of goods, allowing them to reach places outside the airline's destination, extending the airline's services and facilitating cargo owners.