Southwest Airlines currently has a fleet coverage of 86.2% planned but has not yet equipped any aircraft with Starlink as of the latest verified context. The rollout is announced and scheduled to begin in summer 2026, with no confirmed sightings or observations on the BOS->AUS route. Given the rollout status is 'rolling_out' and no aircraft are currently equipped, the probability remains anchored at zero. Despite the high fleet coverage planned, the lack of any equipped aircraft or observations means the probability cannot be raised. No recent news or sightings support a higher estimate.