There is a difference between a ground handling service and a freight forwarder. Ground handling services, notably Menzies, contract with airlines to service their aircraft. They drive the tugs and baggage carts, belt loaders, K-loaders and such and sling the bags. A freight forwarder books available space aboard aircraft and makes the shipper's cargo suitable to load aboard the aircraft and delivers it to the airport (or an airline's receiving dock) and presumably deliver it to its destination at the other end. They may contract somebody else for the final leg of the journey.
