These are the 20 aircraft carriers in service today

USS Gerald R. Ford

Despite aircraft carriers' immense cost, the Navy believes there is no replacing a well-armed, aircraft equipped, sovereign piece of US territory, powered by dual nuclear reactors.

Former Defense Secretary William Cohen was fond of saying that without "flattops" the US has "less of a voice, less of an influence." Evidently, many of the worlds nations also believe this is true.

The last few years have seen a number of interesting developments for aircraft carriers. Some nations, like India and Spain retired aircraft carriers, while China commissioned its first aircraft carrier, and the UK returned to the rather exclusive carrier owners club.

The US commissioned its newest aircraft carrier in 2017 — the USS Gerald R. Ford — the first in the Ford-class. Business Insider got a chance to tour the Ford last year.

In all, 20 aircraft carriers can carry and launch fixed-wing aircraft are currently in service around the world.

Take a look at them here:

Walter Hickey and Robert Johnson contributed to an earlier version of this story.

DON'T MISS: We took a rare tour of one of the US Navy's most dangerous warships — nicknamed the 'Sledgehammer of Freedom'

HMS Queen Elizabeth is the newest aircraft carrier of the Royal Navy, and currently the only active one as well

Length: 932 ft

Commissioned: 2017

Propulsion System: Two Rolls-Royce Marine gas turbine alternators and four diesel engines

History: Queen Elizabeth is the lead ship of her class and one of the newest aircraft carriers in the world. It is currently Britain's only active aircraft carrier, with the second Queen Elizabeth-class aircraft carrier, HMS Prince of Wales, still under construction.

The ship was laid down in July 2009, completed in July 2014, and commissioned in December 2017. Business Insider was able to take a tour of the ship in December, shortly after its commissioning.

Queen Elizabeth is unique from other carriers in that she has two control towers, one for sea operations, and one for air operations.

The carrier is intended to have up to 40 aircraft, with the F-35 intended to be the main fixed-wing jet for the ship. Other aircraft planned to be included are Chinook helicopters, Apache AH MK1 gunships, AW101 Merlin transport helicopters, and AW159 Wildcat anti-surface warfare helicopters.

More recently, Queen Elizabeth docked for the first time at an overseas port when it visited Gibraltar on February 2018. The carrier should be fully operational by 2020.

USS Gerald R. Ford is the US Navy's newest aircraft carrier

Length: 1,106 ft

Commissioned: 2017

Propulsion System: Northrop Grumman nuclear propulsion system and a zonal electrical power distribution system

History: USS Gerald R. Ford was laid down in November 2009, completed in October 2013, and commissioned in July 2017. It is the lead ship of its class, and is planned to be the first of 10 new aircraft carriers.

The ship is still in a testing phase, but is intended to have a planned complement of more than 75 aircraft, mostly F-35Cs. As it is the Navy's newest carrier, new weapons may be added to the ship in the coming years, including lasers.

The ship has a number of new technologies, like the Electromagnetic Aircraft Launch System, which is intended to replace the current steam-powered launch system on current aircraft carriers.

Gerald R. Ford recently tested launching F/A-18F Super Hornets off of its deck last July. It is expected to be fully operational and integrated and into the Navy by 2022.

INS Vikramaditya is the Indian Navy's only aircraft carrier

Length: 930 ft

Commissioned: 2013 (Indian Navy), 1987 (Soviet Navy)

Propulsion System: Eight turbo-pressurized boilers, four shafts, four geared steam turbines

History: INS Vikramaditya is currently India's only aircraft carrier, after India retired the INS Viraat in early 2017.

Vikramaditya is a modified Kiev-class aircraft carrier. It was originally built for the Soviet Navy in 1982, and served the Soviet Union under two names; Baku from 1987 to 1991, and Admiral Gorshkov from 1991 to 1996.

India purchased the carrier in 2004 after years of negotiations for $2.35 billion. After extensive modernization and modification efforts, the Vikramaditya entered full service in the Indian Navy in 2013.

It carries a total of 36 aircraft; 26 MiG-29K and 10 Kamov Ka-31 and Kamov Ka-28 helicopters.

The Vikramaditya recently became the first ship in the Indian Navy to have an ATM on board.

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