Air cargo is used by global importers and exporters when they need to get goods somewhere quickly and reliably. While 90% of everything is shipped by ocean freight air freight connects the world faster, cutting China-US freight shipping time from 20-30 days by ocean to only three days by air cargo.
International air freight and express freight shipments are not the same things.
Express air freight is typically handled by one company (like DHL, UPS or FedEx) that manages the entire shipment lifecycle, with shipping from door to door in under five days. Express air freight shipments are usually smaller (less than one cubic meter and 200 kilograms) than air freight.