Conventional air freight uses the space available on conventional airlines such as Air France, Qatar Airways, Air China, Emirates ... On the other hand, express companies are specialized in the field: DHL, FedEx, UPS, TNT, Aramex. .. Note that the volumetric weight (mentioned in the question above) is calculated differently: by the conventional way, 1 m3 = 167 Kgs while by expressway, 1 m3 = 200 Kgs.