Abstract: The system includes stationary assembly jigs for supporting mechanical structures during assembly thereof, and a plurality of mobile, modular workstations that travel from one assembly jig to another. Each workstation interfaces with the assembly jigs and is configured to facilitate a unique set of work operations on the mechanical structures. The workstations can include worker platforms, parts storage modules, drill and fasten modules, tooless component indexing modules, self-contained cleaning modules, functional testing modules, and others. Docking members on the workstations and the assembly jigs enable the workstations to dock with the jigs for indexing the workstations to the jigs. The assembly jigs can include utility ports and the workstations can include couplers that engage the ports so that electrical, pneumatic, water, vacuum, and/or data communication can be established between the workstations and the jigs.