U.S. Airmen with the 156th Contingency Response Group, Puerto Rico Air National Guard, depart and arrive for Sentry North Exercise at Alpena Combat Readiness Training Center, Michigan, May 31, 2025. Sentry North 2025 focused on operating in a contested environment with adversary aircraft, electronic jamming, and simulated surface-to-air threats, providing a premier joint training opportunity ensuring participating units are combat-ready and interoperable in operationally limited environments.(U.S. Air National Guard photo by 1st Lt. Eliezer Soto) More