There's an old saying: "if it ain't broke, don't fix it." Some aerial warhorses take that pretty literally.
That definitely seems to be the philosophy used by many countries around the world in retaining large numbers of older aircraft as the mainstays of their air forces.
Fighters, attack planes, bombers, and even tankers, all populate this list of old warhorses that have served in wars you only read about in history textbooks today, yet still fly in modern conflicts such as the fight against ISIS in the Middle East.
Though you wouldn't think that military planes like these could serve as long as they have, many remain on the front lines, with the promise of updates to keep them flying for many more years.
From youngest to oldest, here are seven military aircraft that refuse to go away:
7. North American Rockwell OV-10 "Bronco"
At just 52 years old, the Bronco still serves in combat roles as a light air support aircraft, having been brought out of retirement with the US military in 2015 to fly air-to-ground sorties against ISIS in Iraq.
The Bronco first tasted combat in Vietnam, serving in the observer/recon and light attack roles. The Philippine military has also deployed their Broncos to combat zones, recently using them in their own fight against ISIS.
6. Douglas AC-47 "Spooky"
Built off the even older DC-3/C-47 platform, the AC-47 served as a gunship with the US Air Force over the jungles of Vietnam in the mid-1960s before being replaced with the AC-130 series.
With a series of Gatling rotary cannons aimed out the Spooky's left windows, and hard banking turns, this gunship could rain down serious firepower on North Vietnamese military positions, protecting friendly troops from ambushes and enemy advances.
Today, the Spooky — also popularly known as "Puff the Magic Dragon" for the smoke its guns would generate while firing — still serves with the Colombian air force in South America.
5. Mikoyan-Gurevich MiG-21 "Fishbed"
Having first flown in 1956, the MiG-21 has served an astounding 61 years as a frontline fighter with many air forces around the world, and it still flies in such a role today.
Originally designed in the Soviet Union as a cheap, highly-exportable supersonic fighter, it tangled with American aircraft over Vietnam and flew onward with the militaries of a number of Asian and Eastern European nations.
The Indian, Croat, Serbian and Egyptian air forces continue to use the MiG-21 today, along with many other African and Asian countries, though the aircraft's days are numbered with replacement programs looming on the horizon.
4. Boeing KC-135 "Stratotanker"
Also making its debut in 1956, the KC-135 has served continuously with the US Air Force for more than 61 years, and it isn't showing any signs of slowing down!
Built to replace older refueling tankers and medium-range transports, the KC-135 was designed using Boeing's commercially successful 707 airliner as the base model. It has served in virtually every American conflict since, functioning as a transport and a refueler for combat aircraft on the front lines.
According to Air Force brass, plans are in the works to keep the Stratotanker flying for another 40 years, meaning that it'll be over 100 years old by the time it finally retires to the boneyard!
3. Tupolev Tu-95 "Bear"
This old war horse relic of the early Cold War remains in service today with the Russian military, having first taken to the skies in late 1952 as the Soviet Union's primary long-range nuclear bomber.
Extremely loud, very ugly and borderline annoying thanks to the high number of probe flights the Russian Air Force and Navy make near Western borders, the Bear has more than made its mark on the world of military aviation, and will likely continue to do so for at least another 30 years.
2. Boeing B-52 "Stratofortress"
Back when the US Air Force assigned the Space Age-y prefix "Strato-" to many of its shiny new aircraft, the B-52 Stratofortress made its debut - the latest in a long line of strategic bombers from the Boeing Company.
Though designed as a nuclear bomber, the B-52 has only expended conventional munitions throughout its long and storied service life. In recent years, the hulking bomber, affectionately known as the Big Ugly Fat F*cker, or "BUFF," has taken to the skies over the Middle East, bombing ISIS with impunity.
Systems upgrades will allow this American icon to stay in the fight for years to come, at least until a newer strategic bomber comes online for the Air Force.
1. Antonov An-2 "Colt"
The Colt takes the crown (or walker and LifeAlert bracelet) for one of the oldest military aircraft still in service today.
First flying in 1947, two years after the end of WWII, this old warhorse has functioned in a variety of roles — from transport to makeshift bomber.
Today, North Korea and Estonia — among a handful of other countries — still have their Colts flying on active duty, though Estonia will most likely retire theirs soon. The North Korean military uses this old hunk of metal to ferry special operations troops into combat zones at low altitudes.
With Chinese aerospace companies exploring reviving the Colt line in the near future, it's possible that this geriatric plane could keep flying for decades more.