British Airways has a fleet coverage of 50.5% with Starlink rollout currently in progress. Although there are zero confirmed Starlink observations on the LHR->VIE route, the airline's rollout status and fleet coverage ratio set a floor for the probability. Recent news confirms a full fleet-wide deployment commitment starting in 2026, supporting a probability anchored at the fleet coverage ratio. The lack of route-specific sightings and observations limits upward adjustment, so the probability is set at the fleet coverage floor of 0.505.