North Vietnam’s first modern jet base, Phúc Yên, was finished in 1963. Kép was built in 1965, north-east of Hanoi. A CIA intelligence briefing of September 1965, cited by English Wikipedia, said the airfield had been extensively improved, with the runway lengthened to 6,000 ft for jet fighters, and counted eight MiG-15s or MiG-17s on it. In April 1966 the CIA thought a small number of MiG-21s had possibly moved in from Phúc Yên.

For its first two years the airfield itself was not attacked: the first US strike on any VPAF airfield came only in April 1967, more than two years into Operation Rolling Thunder.

That changed on 24 April 1967, when Navy jets of VA-112 and VA-144 struck Kép, the first US attack on a VPAF airfield, according to Wikipedia. Raids on the other MiG bases followed over the next months, including Phúc Yên in October.

A week later Kép produced one of the oddities of the war. On 1 May 1967, during a strike on the airfield, Lieutenant Commander Theodore R. Swartz of VA-76, flying an A-4C Skyhawk from USS Bon Homme Richard, shot down a MiG-17 with an unguided Zuni rocket. It was the only MiG kill by an A-4 — a light attack aircraft — in the whole war. Vietnamese accounts of the engagement were not found in the sources checked.

Vietnam’s official histories long mentioned only a "Group Z" (Đoàn Z). In a 2011 e-dossier for the Wilson Center’s North Korea International Documentation Project, the historian Merle Pribbenow drew on Vietnamese sources to set out the story: a protocol signed on 30 September 1966 sent a company of North Korean MiG-17 pilots to North Vietnam from late October or November 1966, and the contingent flew from Kép from early 1967 through 1968.

In all, 87 North Korean air force personnel served in North Vietnam between 1967 and early 1969. They lost 14 men and claimed 26 American aircraft; the claim is the North Koreans’ own and is not matched by US loss records. The 14 dead were buried in a cemetery in Bắc Giang province, near the base, and in 2002 they were disinterred and repatriated to North Korea.

When the bombing of the North resumed in 1972, Kép was again on the list. The New York Times, cited by Wikipedia, reported fighter-bombers cratering its runway on 15 June 1972 and hitting it again on 18 June. On 18 December 1972, the first night of Linebacker II, Kép, Phúc Yên and Hòa Lạc were attacked to suppress the fighters that might otherwise intercept the B-52s over Hanoi. US claims and Vietnamese claims for the air fighting of that December are given on the air force page and differ sharply.

Kép was one of several MiG fields hit that year. English Wikipedia records that on 27 September 1972 US aircraft destroyed one MiG-21 at Yên Bái, and that on 30 September they destroyed two MiG-21s and a MiG-19 on the ground at Phúc Yên and two MiG-17s at Yên Bái. No comparable figures for aircraft lost on the ground at Kép in 1972 were found in the sources checked, and Vietnamese accounts of the raids were not available.Kép were never meant to destroy the air force on the ground; their stated aim, in the USAF monograph cited by Wikipedia, was to suppress the fighters long enough for the bombers to get through.

Kép remains a working airfield of the Vietnam Air Defence – Air Force. VnExpress reported in November 2023 that Regiment 940 of the Air Force Officer School, which received 12 Yak-130s in late 2021, had moved to Kép from mid-October 2023 to fly training, live firing and bombing sorties every day, the first time the school had deployed a unit away from its home base.

In August 2025 the airfield was the rehearsal ground for the flypast of the 2 September National Day celebrations (A80): VnExpress described Su-30MK2s flying a five-aircraft arrow formation for the first time, six Yak-130s from Regiment 940 (by then described as stationed at Phù Cát) and four L-39NGs in echelon. The permanent resident unit is not named in an official source; English Wikipedia gives Regiment 927.