Air cargo refers to the movement of goods by air.
Air cargo has played an important role in the global economy, and has carved out a niche in terms of transporting high-value, lightweight commodities. It only represents roughly 1 percent of the overall freight movements by weight, and the demand for air cargo is primarily constrained by the costs, as air cargo services can be up to five times the cost of transporting the goods by road, and up to 16 times the cost of sea transport. The aviation sector only contributes 2 percent of all anthropogenic emissions, but is projected to be 70 percent higher than 2005 levels by 2020, even if fuel efficiency improves by 2 percent per year.
There are approximately 2,500 aircrafts that are involved in air cargo. The air cargo industry is made up of different types of market players. Air cargo carriers provide the physical transportation services within a certain segment of the transportation chain (usually from airport to airport), while cargo-only carriers are typically passenger aircraft carriers modified for cargo, and can further be classified into scheduled cargo carriers which provide regularly scheduled cargo-only flights, or dedicated charter operators that are hired for specific deliveries and do not have regular schedules (particularly important for time-sensitive deliveries). Combination carriers, which are estimated to carry around half the global international air cargo, primarily focus on passenger transport but reserve space for transporting cargo. Most carriers operate with a hub-and-spoke network, where the cargo is first transported to a hub and then these are reloaded to another aircraft that will bring the cargo to the final destination. Integrators, which offer integrated solutions to shippers (door-to-door service), specialize in express freight (including international air express services). Freight forwarders, which arrange the transportation chain (shipper to consignee) and prepare the necessary activities for ensuring the smooth transfer of the goods, also play very important roles.
The air cargo industry is highly sensitive to fuel prices and to world trade growth, and is highly affected by economic disturbances such as the economic crisis in the late 2000s. The rise in fuel expenses as well as the costs of meeting security requirements are also important challenges. The industry is also limited by constrained resources such as the limited number of aircrafts and pilots. Trade imbalances make it difficult for operators to fill available cargo space (e.g. demand for cargo capacity from China to the United States will exceed the demand for cargo capacity from the United States to China). The industry is also highly dependent on activities on the ground such as cargo and warehouse handling, which will ultimately impact the demand for air cargo services.
In terms of challenges related to the implementation of energy efficiency and emission reduction measures in the aviation sector, inadequacy in policy frameworks, in information and education, and in political will have been considered by industry experts as the major hurdles to overcome. The implementation of global policies seems to be appropriate, but the process is slow and has to take into consideration the fair treatment of players, countries, and regions.
Green freight programs for the air cargo industry present opportunities for technological solutions to deliver significant fuel and emissions savings. These include: new aircraft designs, the use of composite lightweight materials in the aircrafts, new engines, the use of sustainable alternative jet fuels (second generation biofuels and synthetic fuels), retrofit opportunities such as engine replacement and addition of winglets, the use of electric wheels to reduce main engine operations during taxi modes. Improving aircraft efficiency will result in a notable secondary benefit; as less fuel is needed, the weight of the aircraft is reduced and this, in turn, reduces fuel consumption and emissions. Fuel consumption and emissions from aircrafts can be reduced by adopting a continuous descent approach, or optimized profile descent, which allows for a constant-angle descent to landing instead of a stairstep fashion.
Operational improvements can also significantly reduce emissions and fuel use. For example, the U.S. Federal Aviation Authority NextGen System, which aims to reduce time delays, ensure that the aircrafts operate at optimal elevations and use the most direct paths, has been anticipated to save 1.6 billion gallons of fuel and reduce CO2 emissions by 16 million between 2013 and 2020. Infrastructure improvements at airports, such as the provision of auxiliary power units which can provide electricity for the aircraft during taxiing (and thus eliminate the need to burn aviation fuel) are also important. Other infrastructure improvements involve airfield lighting improvements and the utilization of advanced pavement materials.