(CNN) A pair of nearly 50-year-old planes has been brought out of retirement to fight ISIS.

The Vietnam-era OV-10 Bronco turbo-propeller planes are part of an experiment to see if "light turbo-prop aircraft" are more effective in conducting counterinsurgency operations, a U.S. military representative told CNN this week.

During their deployment, the planes flew 120 combat missions against ISIS targets as part of the counter-ISIS coalition, said spokesman Capt. Bryant Davis of U.S. Central Command, which oversees military operations in the Middle East.

The Daily Beast first reported on the aircraft trials.

The OV-10s were operated by a two-person crew that consisted of a naval aviator and a Navy flight officer, according to the military.

The experiment aims to determine whether slower planes like the Bronco can better support ground troops battling insurgents than more technologically advanced and expensive counterparts such as the F-15 Eagle and F-35 Joint Strike Fighter jets.

The idea is that older aircraft can more cost-effectively fly close air support missions to help U.S. ground troops and pilots better see and attack low-tech insurgents.

Retired naval aviator Cmdr. Chris Harmer praised the aircraft's reactivation, telling CNN it was "an excellent idea."

Harmer, now the senior naval analyst at the Institute for the Study of War, called the OV-10 a "great plane to fly" and said it was likely that U.S. pilots fought over who got the chance to fly it in combat.

Harmer told CNN that the planes were a much more cost-effective alternative than jets like the F-15 or F-35, the latter of which is estimated to cost more than $150 million each.

Photos: In the U.S. Air Force fleet B-52 Stratofortress – The first versions of this long-range heavy bomber flew in 1954. A total of 744 were built, the last of those in 1962. The Air Force maintains 58 B-52s in the active force and 18 in the Reserve. A single B-52 can carry 70,000 pounds of mixed munitions, including bombs, missiles and mines. The eight-engine jets have a range of 8,800 miles. Hide Caption 1 of 24 Photos: In the U.S. Air Force fleet C-130 Hercules transport – A C-130J Super Hercules from the 37th Airlift Squadron flies over Normandy, France, June 3, 2015. First delivered to the Air Force in 1956, the C-130 remains one of the service's most important airlift platforms. More than 140 are still in active units, with more than 180 in the National Guard and a hundred more in the Reserve. The C-130 is powered by four turboprop engines. Hide Caption 2 of 24 Photos: In the U.S. Air Force fleet AC-130 gunships – The AC-130H Spectre and the AC-130U Spooky gunships are designed for close air support, air interdiction and force protection. Armaments on the Spectre include 40mm and 105mm cannons. The Spooky adds a 25mm Gatling gun. Hide Caption 3 of 24 Photos: In the U.S. Air Force fleet F-22 Raptor – The twin-engine F-22 stealth fighter, flown by a single pilot and armed with a 20mm cannon, heat-seeking missiles, radar-guided missiles and radar-guided bombs, can perform both air-to-air and air-to-ground missions. The service has 183 of the Raptors, which went operational in 2005. Hide Caption 4 of 24 Photos: In the U.S. Air Force fleet The single-engine F-35A is the Air Force's eventual replacement for the F-16 and the A-10. The supersonic jets, which will be able to conduct air-to-air and air-to-ground attacks, are just beginning to enter the Air Force fleet. Here, an F-35 Lightning II from the 34th Fighter Squadron at Hill Air Force Base, Utah, flys at Royal Air Force Lakenheath, England, April 15, 2017. Hide Caption 5 of 24 Photos: In the U.S. Air Force fleet B-2 Spirit bomber – The four-engine B-2 heavy bomber has stealth properties that make it hard to detect on radar. Flown by a crew of two, it has an unrefueled range of 6,000 miles and can deliver both conventional and nuclear bombs. Twenty B-2s are in the active inventory. They joined the fleet in 1997. Hide Caption 6 of 24 Photos: In the U.S. Air Force fleet B-1B Lancer bomber – The four-engine jet can fly at 900 mph and carry the largest payload of bombs and missiles in the Air Force inventory. The Air Force has 62 B-1Bs in the fleet. Hide Caption 7 of 24 Photos: In the U.S. Air Force fleet F-15 Eagle – The F-15 Eagle, the Air Force's main air superiority fighter, became operational in 1975. With a crew of one or two, depending on the model, the twin-engine jets are armed with a 20mm cannon along with Sidewinder or AMRAAM missiles. The Air Force lists 249 F-15 Eagles in its inventory. Hide Caption 8 of 24 Photos: In the U.S. Air Force fleet F-15E Strike Eagle – The Strike Eagle is a version of the air superiority fighter adapted to perform ground-strike missions. With a crew of two, the twin-jet can carry and deploy most weapons in the Air Force inventory and operate in any weather. The F-15E was first delivered in 1988. The Air Force lists 219 in its fleet. Hide Caption 9 of 24 Photos: In the U.S. Air Force fleet A-10 Thunderbolt – The A-10 Thunderbolt jets, nicknamed "Warthogs," are specially designed for close air support of ground forces. Key to their armaments is a 30mm Gatling gun. The pilot is protected from ground fire by titanium armor, and the plane's fuel cells are self-sealing in case of puncture. Hide Caption 10 of 24 Photos: In the U.S. Air Force fleet RC-135U – The RC-135U Combat Sent, based at Offutt Air Force Base, Nebraska, provides strategic electronic reconnaissance information to the president, secretary of defense, Department of Defense leaders and theater commanders. Hide Caption 11 of 24 Photos: In the U.S. Air Force fleet An F-15 Eagle takes off from the Andersen Air Force Base, Guam, flight line as two E-3 Sentries are seen in the background. Hide Caption 12 of 24 Photos: In the U.S. Air Force fleet OV-10 Bronco – A 21st Tactical Air Support Squadron OV-10 Bronco aircraft fires white phosphorus rockets to mark a target for an air strike during tactical air control training. Hide Caption 13 of 24 Photos: In the U.S. Air Force fleet A-29 Super Tucano – An A-29 Super Tucano taxis on the flightline during its first arrival, Sept. 26, 2014, at Moody Air Force Base, Georgia. Afghan Air Force pilots trained on the planes that will be used in air-to-ground attack missions in Afghanistan. Hide Caption 14 of 24 Photos: In the U.S. Air Force fleet KC-135 Stratotanker – The four-engine KC-135 joined the Air Force fleet in 1956 as both a tanker and cargo jet. It can carry up to 200,000 pounds of fuel and 83,000 pounds of cargo and passengers in a deck above the refueling system. More than 400 of the KC-135s are flown by active, Air Guard and Reserve units. Hide Caption 15 of 24 Photos: In the U.S. Air Force fleet F-16 Fighting Falcon – The single-engine jet is a mainstay of the Air Force combat fleet. It can perform both air-to-air and air-to-ground missions with its 20mm cannon and ability to carry missiles and bombs on external pods. More than 1,000 F-16s are in the Air Force inventory. Hide Caption 16 of 24 Photos: In the U.S. Air Force fleet C-17 Globemaster transport – The four-engine jet joined the Air Force fleet in 1993 with a primary mission of troop and cargo transport. Each plane can carry up to 102 troops or 170,900 pounds of cargo. The Air Force has 187 C-17s on active duty, 12 in the Air National Guard and 14 in the Reserve. Hide Caption 17 of 24 Photos: In the U.S. Air Force fleet C-5 Galaxy transport – The C-5, with a wingspan of 222 feet, a length of 247 feet and a height of 65 feet, is the largest plane in the Air Force inventory and one of the largest aircraft in the world. The first versions of the four-engine jet joined the force in 1970. The Air Force expects to have 52 versions of the latest model, the C-5M, in the fleet by 2017. Hide Caption 18 of 24 Photos: In the U.S. Air Force fleet CV-22 Osprey – The Osprey is a tiltrotor aircraft that combines vertical takeoff, hover and landing qualities of a helicopter with the normal flight characteristics of a turboprop aircraft, according to the Air Force. It is used to move troops in and out of operations as well as resupply units in the field. The Air Force has 33 Ospreys in inventory. Hide Caption 19 of 24 Photos: In the U.S. Air Force fleet E-3 Sentry AWACS – AWACS stands for airborne warning and control system. This four-engine jet, based on a Boeing 707 platform, monitors and manages battle space with its huge rotating radar dome. The planes have a flight crew of four supporting 13 to 19 specialists and controllers giving direction to units around the battle space. The Air Force has 32 E-3s in inventory. Hide Caption 20 of 24 Photos: In the U.S. Air Force fleet KC-10 Extender – Based on the DC-10 passenger jet, the triple-engine KC-10 is a gas station in the sky with the ability to carry 75 people and 170,000 pounds of cargo. In its six tanks, the KC-10 can carry up to 356,000 pounds of fuel and dispense it while airborne. The Air Force has 59 KC-10s on active duty. Hide Caption 21 of 24 Photos: In the U.S. Air Force fleet T-38 Talon – The twin-engine jet trainer, used by the Air Force to prepare pilots for the F-15E Strike Eagle, F-15C Eagle, F-16 Fighting Falcon, B-1B Lancer, A-10 Thunderbolt and F-22 Raptor, first flew in 1959. Almost 550 are in the active force. Hide Caption 22 of 24 Photos: In the U.S. Air Force fleet U-2 – The single-engine, single-pilot U-2 is used for high-altitude reconnaissance and surveillance. Flying at altitudes around 70,000 feet, pilots must wear pressure suits like those worn by astronauts. The first U-2 was flown in 1955. The planes were used on missions over the Soviet Union during the Cold War, flying too high to be reached by any adversary. The Air Force has 33 U-2s in its active inventory. Hide Caption 23 of 24 Photos: In the U.S. Air Force fleet WC-135 Constant Phoenix – The four-engine WC-135 is used to fly through airspace to detect the residue of nuclear blasts. "The aircraft is equipped with external flow-through devices to collect particulates on filter paper and a compressor system for whole air samples collected in holding spheres," the Air Force says. It has two of these jets in the active force. Hide Caption 24 of 24

Using an F-35 to fly close air support against insurgents would be akin to "buying a brand new Rolls Royce to take the garbage to the dump," Harmer said.

Harmer estimated the cost of flying the more modern jets at $45,000 per hour of flight, while the older Bronco could cost less than $5,000 per flight.

The F-15 Eagle has a cruising speed of 570 mph, while the OV-10 has a cruising speed of 223 mph, according to an Air Force fact sheet.

While he acknowledged that the slower planes were vulnerable to other modern enemy aircraft and anti-aircraft missiles, he said the planes would be "extremely effective" in environments like Iraq and Afghanistan, where the terrorists have very limited anti-aircraft weapons.

More loitering time, better visibility

Paul Scharre, a former Army Ranger who served multiple tours in Iraq and Afghanistan, said these turboprop planes were the perfect middle ground between drones and more technologically advanced jets.

Scharre said that like drones, the OV-10 can loiter over the battlefield for hours, but unlike drones, the pilot has greater visibility of the battlefield and can see the location of enemy forces and attack them directly with machine guns and more bombs and missiles than a drone can carry.

More modern jets travel too fast to see events on the ground and become overly reliant on technology to target enemy combatants, he said. Additionally, these jets consume fuel at a much faster rate, which means they cannot fly over the battlefield for as long as their propeller-powered counterparts.

Scharre, a senior fellow at the Center for a New American Security, told CNN that 15 years of counterinsurgency missions had taken a toll on the technologically advanced and expensive American fighter jet fleet, saying a jet "can only have so many flying hours before it is worn out."

Both Scharre and Harmer said that these light attack aircraft would be in high demand by U.S. Special Operations forces because of their ability to provide persistent surveillance and close air support and target enemy forces up close without risking friendly fire casualties because the pilots are flying slow enough to visually distinguish between enemy and friendly forces.

However, Harmer and Scharre think that resistance from higher-ups in the military will hamper the drive to acquire these retro aircraft and that the Air Force is too focused on the more expensive F-35 to give much consideration to embracing a 50-year-old technology.

The Central Command representative told CNN that the results of the initial experiment have been passed on to the Office of the Secretary of Defense Joint Requirements Oversight Council and that the information will help Pentagon "decision makers determine if this is a valid concept that would be effective in the current battlespace."

He added, "because the report is still a draft, it would be inappropriate and premature to provide details regarding any findings or potential recommendations."

"The American way of fighting since World War II has been to have superior technology. There has been a constant focus on leading technological advancement that is on cutting edge," Harmer said.

But Scharre is optimistic that these effective aircraft will find a niche within the military, possibly with Air Forces Special Operations acquiring some planes to support Special Operations forces.

The need for close air support in the fight against ISIS also helped convince the Air Force to reconsider plans to retire the A-10 Warthog, a 1970s-era ground attack jet.

Scharre also thinks that these turboprop aircraft will prove ideal for equipping and arming U.S. partners that are fighting insurgencies and terrorists.

In January, the United States also provided Afghanistan with four turboprop A-29 Super Tucano planes, the Afghan air force's first fixed-wing combat aircraft.