Air cargo does not travel loose. It travels in unit load devices — the containers and pallets that lock into an aircraft hold — and their shapes are dictated by the curve of the fuselage. That is why air cargo dimensions look arbitrary: they are not boxes, they are slices of a cylinder.
Dimensions below are the common nominal figures for each ULD type. Actual usable space varies by aircraft, airline and the individual unit, and contoured units lose volume at the angled edges. Confirm with your forwarder before building pallets to the limit.
The main types
| Code | Common name | Approx. base | Typical use |
|---|---|---|---|
| AKE / LD3 | LD3 container | ~156 x 153 cm | The workhorse. Widebody lower deck, contoured one side |
| AKH / LD3-45 | Low-height LD3 | ~156 x 153 cm | A321 and similar lower holds, reduced height |
| ALF / LD6 | LD6 container | ~318 x 153 cm | Two LD3 footprints joined, contoured both sides |
| AMA / M1 | Main deck container | ~318 x 244 cm | Freighter main deck, large volume |
| PMC / P6P | 96 x 125 inch pallet | ~244 x 318 cm | The standard air pallet, lower and main deck |
| PAG / P1P | 88 x 125 inch pallet | ~224 x 318 cm | Narrower pallet, widely used |
| PLA / LD7 | LD7 pallet | ~224 x 318 cm | Older widebody lower deck |
Height is the constraint that costs you money
The number that decides your options is build height, and it differs sharply by deck:
- Lower deck (belly) of a widebody — commonly around 160 cm maximum build height.
- Main deck of a freighter — commonly around 300 cm, sometimes more.
- Narrowbody belly — substantially less, often around 114 cm, and frequently bulk-loaded loose rather than containerised.
Cross the lower-deck height limit by a few centimetres and your cargo can no longer travel in the belly of a passenger aircraft. It now needs a freighter, which flies less often on most routes and prices differently. A pallet built 5 cm too tall can cost days and a substantial premium — which is why the height check belongs in your packing specification, not at the airport.
Contour: why the corners disappear
An LD3 is contoured to sit against the curve of the fuselage, so one lower corner is cut away. Pallets built for lower-deck loading are similarly contoured at the top edges by the build. The practical effect is that nominal ULD volume overstates what you can actually load unless your cartons are small enough to step the stack. Dense, low, uniform cartons use a ULD far better than tall irregular ones.
What this means for your booking
- Give dimensions per piece, not just totals. A single over-height piece changes the aircraft type for the whole shipment.
- Check chargeable weight before you build. Air freight bills the greater of actual and volumetric weight — use the chargeable weight calculator.
- Build to the deck you are buying. Ask your forwarder whether the routing is belly or freighter before finalising pallet height.
- Watch the tare. ULD weight counts against the aircraft limit but is not your cargo — do not include it in your own weight declaration.
- Do not exceed the load line or overhang the base. Airlines reject non-conforming builds, and rebuilding at the airport is charged and slow.
When air is worth it at all
ULD planning only matters once you have decided air is the right mode. The trade-off is covered in sea freight vs air freight and priced in how air freight pricing works. For urgent volumes beyond scheduled capacity, air charter vs scheduled air freight covers when a charter earns its cost.
Packaging drives all of it — see export packaging and palletisation.
Post your piece dimensions and let forwarders quote the routing, or find air freight forwarders on your lane.
