As of 2026, having United Airlines Premier status does not qualify you for "complimentary" upgrades on Lufthansa flights. While both airlines are Star Alliance partners, complimentary upgrades are generally restricted to an airline's own "metal" (aircraft). However, you can use United PlusPoints to request upgrades on Lufthansa-operated flights, provided you are booked in eligible fare classes (typically Y, B, M, U, H, Q, or V for Economy to Premium Economy/Business). In early 2026, United and Lufthansa expanded their digital integration, allowing Premier 1K and Global Services members to confirm these PlusPoints upgrades instantly through the United app for many transatlantic routes. If you hold Premier Gold status or higher, you are recognized as Star Alliance Gold, which grants you "priority" on the standby list for seats, lounge access, and extra baggage on Lufthansa, but you will still need to use miles or upgrade certificates to move to a higher cabin.