During November 2001, AFRL (US), Defence R & D Canada and QinetiQ (on behalf of the UK MoD), conducted the first in a series of simulation trials to investigate the potential of an international collective environment for real-time, ground-based aircrew training. The trial involved simulating a mixed air-to-air and air-to-ground package using manned virtual simulators in the US for the friendly force and manned simulators, computer generated forces, and human role players at the Bedford site in the UK for both the friendly and enemy forces. The Canadian site was a passive stealth node on the network. The simulated operational environment known as the "scenario" was designed to be as realistic as possible. Front-line, mission ready crews manned the simulators, while other military personnel took the roles of the command chain for both friendly and hostile forces. This allowed the simulated missions to be run as they would be in a real operational environment, with full pre-sortie briefings, crew planning, sortie execution and debriefing all conducted via a secure long haul link between the countries. The implementation of the trial infrastructure involved significant development and integration effort, covering aspects such as long-haul secure data and voice communications; scenario development and management; data recording and analysis tools; planning, briefing and debriefing systems; and computer generated forces. This paper describes the trial infrastructure, explains its development, and reviews the lessons learned during its development and use.