The 45th Fighter Squadron was activated Dec 1, 1940 as the 45th Pursuit (Fighter) Squadron, one of three squadrons assigned to the 15th Pursuit Group, Wheeler Field, territory of Hawaii. Until 1941 they flew the P-26. They endured Japanese attack on Oahu on Dec 7, 1941. The squadron provided air defense for the Hawaiian Islands in P-36 and P-40 aircraft over the Pacific from January 1942 - October 1943.
The 45th Pursuit Squadron was re-designated as the 45th Pursuit Squadron (Interceptor) Feb. 12, 1942. Three months later on May 15, 1942, "pursuit" was dropped and the squadron was re-designated as the 45th Fighter Squadron.
The squadron flew combat missions in the Central Pacific from Oct. 23, 1943 until March 11, 1944, and in the Western Pacific from March 12, 1944 until Aug. 14, 1945. Missions were accomplished using P-47 and P-51 Mustang aircraft.
Flying its first very long range mission to Japan April 7, 1945, the 45th Fighter Squadron provided fighter escort for the B-29 Superfortress that attacked the Nakajima aircraft plant near Tokyo, earning them a distinguished unit citation for their efforts.
During this two-year period, the 45th Fighter Squadron claimed destruction of 11 enemy aircraft Jan. 26, 1944, near Aur Atoll, Marshall Islands.
March - August 1945, they provided air defense for Iwo Jima; neutralized the Bonin Islands; and provided fighter escort for B-29s attacking the Japanese home islands.
The squadron received the Distinguished Unit Citation: Japan April 7, 1945.
The squadron was inactivated Oct. 15, 1946.
On Sept. 11, 1952, the squadron was re-designated as the 45th Fighter-Interceptor Squadron. The squadron was activated and assigned to the 4709th Defense Wing, Suffolk County AFB, N.Y., Nov. 1, 1952.
On Feb. 16, 1953, the squadron was assigned to the 519th Air Defense Group as part of the Air Defense Command commitment. The squadron's mission was to provide air defense in the Northeast United States flying the F-86 aircraft.
The 45th Fighter Squadron was assigned to Seventeenth Air Force and transferred to the United States Air Forces Europe in Sidi Slimane, French Morocco, North Africa May 28, 1953, where they remained until Jan. 8, 1958.
On Oct. 8, 1954, the squadron was re-designated as the 45th Fighter-Day Squadron. The pilots flew the F-86F Sabre aircraft until March 1956, when they received new F-100C Super Sabres.
While assigned to USAFE, they deployed air defense in Northwest Africa from June 1953 - February 1956 and from January 1957 - October 1957. They also conducted F-100 transition training from May - December 1956.
The squadron was inactivated Jan. 8, 1958.
On April 17, 1962, the squadron was re-designated and activated as the 45th Tactical Fighter Squadron assigned to Tactical Air Command. They flew the F-84 aircraft from 1962 - 1971.
The 45th Tactical Fighter Squadron was organized and attached to the 15th Tactical Fighter Wing, Mac Dill AFB, Fla., July 1, 1962.
From October 1962 - June 1971, the squadron participated in exercises, operations and tests of Tactical Air Command, including combat missions while on temporary duty in Southeast Asia, April - August 1965. While operating out to the Ubon Royal Thai Air Base they had the first USAF MIG kill of the Vietnam War.
The unit received an Air Force Outstanding Unit Award for the period Jan. 1, 1965 - June 1, 1966.
For the next five years, the 45 TFS served as a replacement training unit for F-4 pilots headed to Southeast Asia.
The unit received an Air Force Outstanding Unit Award for the period Jan. 1, 1969 - Dec. 31, 1969.
The squadron was inactivated again July 1, 1971.
The 45th Tactical Fighter Squadron was reactivated Oct. 1, 1973, and assigned to 930th Tactical Fighter Group, Grissom AFB, Ind. They flew the A-37 Dragonfly, an upgraded version of the T-37 trainer.
On July 1, 1975, the 45 TFS was assigned to the 434th Tactical Fighter Wing, Grissom AFB, Ind.
In 1981, they transitioned to the A-10 Thunderbolt II, commonly referred to as the Warthog.
From July 1, 1987 - Sept. 30, 1994, the squadron was reassigned to the 930th Tactical Fighter Group (later 930th Fighter Group; became 930th Operations Group), Grissom AFB, Ind.
On Feb. 1, 1992, the unit was re-designated as the 45th Fighter Squadron ("Hoosier Hogs").
On Sept. 30, 1994, the 45 FS was inactivated.
On November 1, 2009 the 45th Fighter Squadron was re-activated as an associate unit with the 355th Fighter Wing, Davis-Monthan AFB, Ariz., assigned to the 917th Wing, Barksdale AFB, La. The mission of the 45th Fighter Squadron is the train A-10 pilots.
On January 1, 2011, the 917th Wing was deactivated and the 45th Fighter Squadron realigned under the 924th Fighter Group at Davis-Monthan AFB, Ariz. which was activated on the date date.
(Current as of January 2011)