Belly Cargo

Belly cargo refers to commercial freight carried in the lower deck hold of a passenger aircraft, in the space below the main passenger cabin floor. On widebody jets, this cargo capacity is a significant revenue source that airlines actively sell to shippers and freight forwarders, transforming the passenger aircraft into a dual-purpose vehicle that generates income from both the seats above and the hold below. On many international routes, belly cargo revenue covers a material portion of the flight's total operating cost.

What Is Belly Cargo?

The lower deck of a widebody passenger aircraft is divided into cargo compartments that can carry standardized containers called Unit Load Devices (ULDs), loose freight, and passenger baggage in a combination that varies by flight. ULDs—aluminum pallets and containers in standardized dimensions—allow freight to be packed on the ground and loaded quickly with automated handling equipment, minimizing aircraft ground time. The main belly hold configurations use LD3 containers (the most common, holding approximately 4.5 cubic meters) arranged in rows across the aircraft width.

A Boeing 777-300ER, for example, has approximately 200 cubic meters of cargo hold capacity with a maximum payload of around 20,000 kilograms in the belly, depending on passenger load. The Airbus A350-900 offers a similar 172 cubic meters with comparable weight allowance. These are not trivial numbers—on a transatlantic flight, the belly cargo might represent 15 to 25 percent of total revenue depending on freight market conditions. Emirates SkyCargo, the freight division of Emirates airline, is one of the world's largest cargo carriers despite operating exclusively on passenger widebody aircraft because of the sheer scale of belly capacity in its 777 and A380 fleet.

Narrowbody aircraft have much more limited belly cargo capacity. A Boeing 737-800 carries passenger baggage and a modest amount of freight in three small compartments totaling roughly 45 cubic meters—not enough to accommodate ULD containers. Cargo on narrowbodies is typically loose-loaded by hand, which is slower and less suitable for commercial freight forwarding operations.

How It Works in Practice

Airlines sell belly cargo capacity to freight forwarders and direct shippers through their cargo divisions, which operate largely independently of the passenger sales organization. Cargo pricing is driven by demand, route competitiveness, aircraft type, and commodity—temperature-sensitive pharmaceuticals command higher rates than standard general cargo because they require special handling and may displace lower-value goods. High-value goods like electronics, luxury fashion, and cut flowers from Kenya to European markets generate premium rates on specific routes.

The relationship between passenger load and cargo capacity is dynamic. Weight-limited flights—those where total weight of fuel, passengers, baggage, and cargo approaches maximum takeoff weight—require airline cargo managers to prioritize the most revenue-generating mix. A fully booked transatlantic widebody might have to offload lower-paying general cargo in favor of high-rated express freight. Conversely, a thin passenger load leaves more weight available for cargo, allowing the airline to accept heavier shipments that might be refused on a busier flight.

During the COVID-19 pandemic, when international passenger flights were largely grounded, airlines discovered the limitations of being purely belly-cargo dependent. With no passenger revenue, many converted passenger aircraft to carry only cargo—removing seats and loading freight on the main cabin floor (so-called "preighter" operations)—demonstrating both the importance of cargo revenue to airline economics and the adaptability of passenger aircraft to cargo roles.

Why It Matters for Airlines

Belly cargo is a high-margin revenue stream for airlines because the infrastructure to carry it—the aircraft, its fuel, its crew, and its fixed costs—is already committed to the passenger service. The incremental cost of loading cargo into the belly is primarily ground handling and the small fuel burn penalty from the added weight. This structural advantage makes belly cargo one of the most profitable revenue lines available to passenger airlines on busy international routes.

The importance of belly cargo varies enormously by route. Transatlantic and transpacific routes between major commercial centers—New York, London, Frankfurt, Tokyo, Hong Kong—generate the highest belly cargo demand and rates, driven by the concentration of international trade and e-commerce fulfillment along these corridors. Middle Eastern carriers like Emirates, Qatar Airways, and Etihad have built powerful cargo operations by positioning their hubs as freight interchange points on the Asia-Europe trade corridor.

Key Facts and Figures

• Boeing 777-300ER belly cargo capacity: approximately 200 cubic meters, carrying up to ~24 LD3 containers plus bulk cargo
• Global air freight market: approximately $130 to $150 billion annually, of which belly cargo represents roughly 55 to 60 percent
• Emirates SkyCargo revenue: approximately $5 to $6 billion annually from belly cargo and dedicated freighters
• LD3 container dimensions: 60.4 × 61.5 × 64 inches (external); maximum weight approximately 1,588 kilograms
• Belly cargo yield (revenue per kilogram): typically $2 to $4 for general cargo, $5 to $15 for pharmaceuticals and express
• Narrowbody belly cargo capacity: typically 15 to 45 cubic meters, insufficient for ULD containers

Related Concepts

Belly cargo is a function of the widebody aircraft's lower deck design and cabin configuration decisions that determine how much of the fuselage is allocated to passenger versus cargo space. It connects to maximum takeoff weight, which is the ultimate constraint governing how much total payload—passengers, baggage, and cargo—any aircraft can carry. Aircraft range interacts with belly cargo because heavier cargo loads reduce range, requiring airlines to make payload-range trade-offs. The economics of belly cargo also relate to aircraft conversion, since when passenger aircraft retire or markets shift, belly cargo operators must decide whether to convert the aircraft to a dedicated freighter.