This industry comprises establishments primarily engaged in furnishing air delivery of individually addressed letters, parcels, and packages (generally under 100 lbs), except by the Postal Service. While these establishments deliver their consignment by air, the initial pick-up and the final delivery are often made by other modes of transportation, such as truck, bicycle, or motorcycle. Separate establishments of air courier companies engaged in providing pick-up and delivery only, "drop-off points", or distribution centers are all classified here.