About 55% Starlink odds, weighted to recent UA5821 flights. A firm answer comes about 2 days before departure, once the aircraft is assigned.
Based on 50 recent flights; Starlink found in 8 of 10 Wi-Fi checks since Feb 17, 2026 (last N107SY, Sep 19, 2026).
Aircraft seen on UA5821: Embraer E-175, Mitsubishi CRJ-200LR.