Naval Air Facility Adak (IATA: ADK, ICAO: PADK, FAA LID: ADK), was a United States Navy airport located west of Adak, on Adak Island in the U.S. state of Alaska. After its closure in 1997, it was reopened as Adak Airport. The facility was designated a National Historic Landmark for its role in World War II, although most of its elements from that period have been demolished or lie in ruins.

On June 6/7, 1942, the Japanese Navy and Army participated in the only invasion of the United States during World War II through the Aleutian Islands of Kiska and Attu as part of the Aleutian Islands Campaign. Despite the first loss of U.S. soil to a foreign enemy since the War of 1812, the campaign was not considered a priority by the Joint Chiefs of Staff. British Prime Minister Churchill stated that sending forces to attack the Japanese presence there was a diversion from the North African Campaign and Admiral Chester Nimitz saw it as a diversion from his operations in the Central Pacific. Commanders in Alaska, however, believed the Japanese occupiers would establish airbases in the Aleutians that would put major cities along the United States West Coast within range of their bombers and once the islands were again in United States hands, forward bases could be established to attack Japan from there.

The establishment of Adak Army Airfield (Code Name A-2, also "Longview") on 30 August 1942 gave the United States Army Air Forces a forward base to attack the Japanese forces on Kiska Island. The landing was made in a storm and within a week additional forces, including the 807th Engineer Aviation Battalion were landed on the island at Kuhluk Bay. However, the island had not been properly surveyed to find a suitable site to build the airfield. A very quick survey of the coast located a tidal marsh which had a firm foundation of sand and gravel beneath it. Work began on 2 September with the construction of an enclosing dike around the marsh and a system of drainage canals drain off the water, followed by scraping off the topsoil to reach the gravel underneath. Additional gravel and then a sand runway was laid down. By 10 September enough construction had been completed that a 73d Bomb Squadron B-18 Bolo successfully landed on the runway. A 5,000 ft Pierced Steel Planking was laid down shortly afterward and the transports from the 42d Troop Carrier Squadron arrived the following day, landing on compacted sand next to where the matting was being laid.

Tents were erected, a rudimentary electrical system, radios and some rough streets were laid down and by the end of September Adak Army Airfield was home to several 36th Bomb Squadron B-17 Flying Fortress heavy bombers; 54th Fighter Squadron P-38 Lightnings, and five B-24 Liberators of the 21st and 404th Bombardment Squadrons. Additional P-38s were flown in along with some P-39D Airacobras of the 42d Fighter Squadron which had been providing air defense for Kodiak. Even while aircraft were landing, construction continued at a rapid pace to cover the PSP with several layers of asphalt and construct additional station facilities.

During World War II, the following units were assigned to Adak AAF:

By 13 September, enough construction had been completed at Adak to justify the movement of operations from Fort Glenn AAF on Umnak to the new airfield which was 400 miles closer to the Japanese forces on Kiska. The 250-mile distance from Adak allowed multiple combat sorties each day to be carried out, weather permitting. This was particularly true for the fighters, which were now within easy striking range of enemy targets. Previously, only the long-range P-38s had been able to reach Kiska from Fort Glenn AAF, and only with great difficulty. The Japanese forces on Attu, (430 miles from Adak) however, remained only within the range of the B-24 Liberators, although the P-38s could fly escort missions. With the movement of combat operations to Adak, Fort Glenn and also Fort Randall AAF at Cold Bay became support and staging airfields supporting the front line.

The first major combat mission of the Aleutian Campaign from Adak occurred on 14 September 1942 when thirteen B-24 Liberators and one B-17 Flying Fortress; supported by fourteen P-38 Lightnings, fourteen P-40 Warhawks and seven P-39 Airacobras attacked Kiska harbor. Instead of coming in at high altitudes, the attack was a low-level sweep over the water that caught the Japanese defenses off-guard. The P-39s came in first to suppress the anti-aircraft fire with their 37mm cannon fire. The P-40s then strafed the harbor, attacking the Nakajima A6M2-N "Rufe" float plane fighter/bombers. After the fighters, the heavy bombers attacked, also at low level, dropping 1,000 bombs on the harbor installations. Eleventh Air force lost two P-38s in an airborne collision and claimed five Japanese aircraft shot down. Several cargo ships and minesweepers were hit with the harbor facilities and float planes taking a considerable beating. It would be a month before the Japanese could send out a reconnaissance aircraft from Kiska to fly over Adak. Although the Americans were not aware of it at the time, this raid essentially ended the ability of the Japanese to send out offensive strikes from Kiska and so effectively crippled the facility that the Japanese began withdrawing their shipping from the harbor. The garrison dug in and began to practice anti-aircraft drills.

Attacks continued against Kiska with high intensity through the fall and end of 1942. Japanese operations from Kiska consisted of a few reconnaissance missions over Adak or a nuisance bombing mission where an aircraft would drop one or two bombs without causing any significant damage. By the end of October, the Japanese had decided to pull out most of its garrison to Attu, which they believed was worth retaining, and began transporting additional units from Hokkaido to Attu and began upgrading their defenses.