The F-4 Phantom, which entered service with the U.S. Air Force in 1960, was America's premier fighter until the 1980s, with more than 5,000 units produced over 23 years and exported to ten customers on four continents. The fighter-bomber's breakthrough came during the Vietnam conflict, where it was extraordinarily successful and scored major victories, but it got even better when design adaptations culminating in the F-4E in 1965 produced an air superiority fighter that was unrivaled in the Western world. The operating costs of the aircraft were low enough that the U.S. Air Force could afford to use the F-4 as its primary fighter for many years, until its successor, the F-15 Eagle, came along. Many countries those in important strategic positions, such as NATO members on the front line, Turkey, Greece, Britain and Germany, Japan, and Iran, on the front line with the Asian regions of the USSR, and Israel, which was facing Soviet-aligned Arab states such as Syria and Iraq. Of the F-4's eleven overseas customers, four still operate the aircraft, the newest of which is more than 40 years old, and all are expected to replace their Phantoms before 2030. Japan and Egypt also operated F-4s until 2021 and 2013, when they were belatedly retired to be replaced by the F-35 and MiG-29M fighters. Let us look at the air forces to learn about the current status of the remaining F-4s in service. South Korea's F-4 Phantoms The Republic of Korea Air Force (ROKAF) currently has nine squadrons of Vietnam War-era F-4E and F-5E/F third-generation fighters, which form an incredibly sizable proportion of its fleet of 23 fighter squadrons. A Republic of Korea Air Force RF-4C Phantom taxis to the runway at Kunsan Air Base, Republic of Korea, for a mission May 11 during exercise Max Thunder 09-01. The exercise is a 7th Air Force-designed, bilateral training opportunity that aims to test aircrews' warfighting skills in realistic combat situations that combine both ROKAF and U.S. Air Force flying and maintenance personnel. (U.S. Air Force photo/Senior Airman Gustavo Gonzalez) But only one squadron of 30 F-4E fighters, which have been refurbished and modernized, remains in service. Even with all this, the country hopes to replace them by the end of this decade with Lockheed Martin's F-35As, with an order for up to 60 units already in the pipeline. The Hellenic Air Force's F-4 Phantoms Greece has a single squadron of 34 F-4E Phantoms operating with other more modern fighters such as F-16s and Mirage-2000s also in final operational phase. Hellenic Air Force F-4 RIAT 2017 The Greek F-4s are the most capable in the world in terms of air-to-air performance and integrate modern AIM-120 AMRAAM active radar-guided air-to-air missiles, which provide superior capability beyond visual range to many fourth-generation aircraft. The Hellenic Air Force's receipt of second-hand Rafale fighters from France could see these aircraft replace the F-4s currently in service. Turkey and its F-4s, uncertain future Turkey is the largest foreign operator of the F-16 Fighting Falcon but maintains a squadron of F-4s for ground attack roles. Turkish Air Force F-4E Phantom & KC-135R Take Offs at RIAT 2019.Photo: ElliotL- CBGSpotter Initially, the Turkish air force had planned to replace the F-4s with F-35As, but there is currently an uncertain horizon on this issue due to the country's expulsion from the F-35 program, and with this, it is not ruled out that eventually, F-16s will replace the F-4 phantom. Iranian F-4 Phantom, replacement by drones? The Iranian Air Force is the largest remaining operator of the F-4 Phantom and is the only operator of the older F-4D variants flying alongside a larger number of more modern F-4Es. F-4s form five of the country's seventeen fighter squadrons, with an additional squadron of RF-4E reconnaissance aircraft also operational, for a total of about 70 Phantoms in service. Iranian Air Force F-4 Fighter jet displayed at press conference in Isfahan Photo: Radio Farda. Iran. There has been speculation about replacing them with Russian SU-35 fighters, but their operating costs, higher even than those of the F-4, would mean that the air force would have to adjust its current capabilities, but Iran's ability to produce all spare parts and armament for its Phantoms domestically, and to refurbish and modernize the aircraft, means that the Iranian Air Force may be reluctant to part with the Phantoms and go back to relying on foreign sources for upgrades and parts. The F-4 may remain in service until the country develops a fighter of its own capable of replacing it. A final option, and one that is not ruled out for the time being, is that Iran's large, unmanned combat aircraft (UCAVs) industry, which has produced formidable combat-proven stealth designs, may provide an unmanned successor to the F-4 by leveraging what is perhaps the greatest strength of the country's defense sector.