ULD
A Unit Load Device (ULD) is the standardised pallet or container used to load cargo, mail, and baggage onto wide-body aircraft. ULDs allow cargo to be pre-built away from the aircraft and loaded quickly during the turn — critical for tight aircraft scheduling.
Common ULD types include: AKE (LD3 lower-deck container, ~1.5 m³), AKH (LD3-46W reduced height), PMC (P6P main-deck pallet, ~10.6 m²), AMA (M1 main-deck container), and various specialised types for live animals, vehicles, or temperature-controlled cargo.
ULD management is a major operational concern — they're tracked as individual assets with status (free / allocated / loaded / in-transit / returned / damaged), pooled between airlines under interline agreements, and reconciled with weight & balance calculations for the aircraft.