Different kind of goods can be transported by air, which will be presented to you on this page.
In terms of weight, only 1 % of globally transported goods are transported by air, but these represent 30 % of the value of goods transported. Air freight tends to be used to ship mainly small, light goods that tend to be of high value.
The most common types of goods being transported by air are
emergency shipments
perishable goods (goods with a physically limited shelf life, goods with a rapid loss of value due to market conditions, e.g. clothing)
goods with a high value-to-weight ratio (electrotechnical, precision mechanical, pharmaceutical and optical products, e.g. computer processors, PCs, cell phones, tools, medicines, cameras, etc., as well as art and other valuables)
The three groups of goods, that are mainly shipped by air freight in Germany are electronic goods, machines and optical devices.
In Germany, prior to Covid-19, in 2019 4.7 million tonnes were handled at German airports and 61.5 million tonnes worldwide. In 2020, German airports handled 4.6 million tonnes, the airports worldwide handled 56.1 million tonnes.
For air transport, air traffic containers are being used. Those containers are unit carriers and are adapted to the shape of the plane (figure "Air containers in an airplane").
The following pictures are showing different kinds of air traffic containers. As you can see, the shapes of the containers are adapted to the shape of the airplanes. Containers for the lower deck are having a flattened side and corner, so that they fit better to the round shape of the airplane. Containers for the middle deck don‘t always need to have this adapted shape, but for the containers at the edge, a lot of times the upper corner is flattened as well.
Transport
Air freight transport can be organised either as a forwarder or integrator transport.
The difference between the two types of transport is the runtime of the transport and the weight transported.
While the classic D2D (Door-to-Door) Transport has set the focus on all cargo and takes around 5-6 days, the focus of the integrator D2D Transport is set to cargo up to 500kg and takes around 2-3 days.
The different stakeholders involved in the classic and the integrator D2D transport are shown in the figure "Classic and Integrator D2D Transport".
Air freight transport is often organised in a Hub-and-Spoke-Network.
A hub & spoke network is a special network with a certain number of nodes between which a flow of goods exists. A subset of centrally located nodes serves as a transhipment point (hub). The remaining nodes (end nodes) are connected in a star shape by a spoke and usually with one hub. The flow of goods between two nodes is direct if both nodes are hubs or one of the two is a hub and both are connected by a spoke. Otherwise, the flow is routed via at least one other hub. In contrast to complete networks, in which every node is connected to every other node and direct transports take place, a hub-and-spoke network contains significantly fewer connections. The transport volume per connection is greater, so larger transport units can be selected and thus transport costs saved. However, the transport times between the end nodes of such a network are usually longer than in complete networks. Hub-and-Spoke networks are used in air traffic, by large freight forwarders, parcel services and the postal service as well as computer and communication networks. (Domschke et al. 2018, S. 10)
The following figure "Hub-and-spoke systems" shows a hub-and-spoke network. In this case, the hub in Germany is located in Frankfurt. Some of the most important hubs worldwide are marked in red.
The figure also shows the different amounts of connections. By using a hub and spoke structure, the number of connections can be reduced to n.
More than half of the total air freight volume is distributed among 15 cargo hubs worldwide like Memphis, Hongkong, Tokio, Frankfurt, Shanghai, Singapore and Paris. In Germany, the air freight is concentrated in Frankfurt and Leipzig/Halle (=73 % of the total air freight volume). 92 % of the total air freight volume is handled in Frankfurt, Leipzig/Halle and Köln/Bonn.
Flämig, H., Sjöstedt, L., Hertel, C. (2002): Multimodal Transport: An Integrated Element for Last-Mile-Solutions? Proceedings, part 1; International Congress on Freight Transport Automation and Multimodality: Organisational and Technological Innovations. Delft, 23 & 24 May 2002. (modification of Sjöstedt 1996)