In the 1920s Mafraq was used as a base for aircraft and armoured cars of the RAF. By 1931 Mafraq, which is situated on a large flat desert expanse five miles from the Syrian border, was used as the major staging and refuelling post for international flights and for the transfer of air supplies, personnel, freight and mail.
In 1951 the station was being rapidly developed with new buildings and a concrete runway laid. RAF Mafraq was evacuated and handed over to the Jordanian Government on May 31, 1957. The base stayed unused until 1958 when the RJAF took over and it was named King Hussein Air Base in June 1959 with No 1 Fighter Squadron (Hunters) and later No 2 Squadron (Vampires) moving from Amman.
Flying training started in 1960 with No 4 Squadron equipped with Chipmunks, but was later disbanded.
The Base was attacked in the 1967 War with aircraft, runway and one of the hangers destroyed. It was then temporarily repaired but not used on a regular basis as the pilots were stationed in Iraq until 1968. In 1969 it was decided complete resurfacing was needed so the Hunter squadron redeployed to Amman and then to Syria.
In September, 1970 the Hunter squadron was moved temporarily to PHAB, H5 as the Mafraq base was a vulnerable target, being situated so close to the Syrian border and threatened by Iraqi forces that were deployed in Jordan.