Lajes Field

Lajes Field, officially designated Air Base No. 4 (Base Aérea N.º 4, BA4), is a multi-use airfield located near Lajes on Terceira Island in the Azores, Portugal. Constructed in 1934 by the Portuguese military, it has been continuously operational since its inception. The base is jointly operated by the Portuguese Air Force, which maintains Base Aérea N.º 4 and the Azores Air Zone Command, and a United States Air Force detachment unit, the 65th Air Base Group, under United States Air Forces in Europe - Air Forces Africa. A regional air passenger terminal also operates from the airfield, facilitating civilian air traffic.

During World War II, the airfield's runway was expanded, and it became a crucial transit point for Allied aircraft. A joint agreement between British and U.S. military representatives in 1943 formalized its use for ferrying aircraft to Europe. Post-war, control reverted to Portugal in 1946, though a Status of Forces Agreement (SOFA) has allowed continued U.S. military presence. Lajes Field played a role in Cold War operations, supporting maritime patrol aircraft tracking Soviet submarines and serving as a key stopover for U.S. airlift missions, notably during Operation Nickel Grass in 1973.

Currently, Lajes Field supports NATO and non-NATO armed forces for transatlantic transport, VIP movements, exercises, and humanitarian missions. Its strategic mid-Atlantic location makes it a diversion airport for medical or mechanical emergencies for various aircraft types. The Portuguese Air Force units stationed there include detachments of Squadron 502, operating EADS CASA C-295s for transport and maritime patrol, and Squadron 751, flying AgustaWestland AW101 Merlins for search and rescue. The U.S. military contingent, reduced in 2012, continues to provide base and en route support for authorized aircraft.