Southwest Airlines is currently in a rolling_out status with a high fleet coverage ratio of 86.2%, but no aircraft are confirmed equipped yet and no observations exist on the BNA->SMF route. Perplexity context indicates zero equipped aircraft as of May 2026, with rollout expected to begin in summer 2026. Given the rollout status and high fleet ratio, the probability is anchored conservatively at 0.30 as a floor, reflecting the announced rollout and high fleet coverage potential, but no direct route observations or sightings to increase confidence.