Stocky, but agile. It's one way to describe Lockheed Martin Corp.'s latest concept for a new F-16 Fighting Falcon variant for the Indian Air Force.

In a pitch to the country Wednesday, the company unveiled the F-21 as a single-engine fighter with "innovative technologies derived from Lockheed Martin's [F-22 Raptor] and [F-35 Joint Strike Fighter] -- the world's only two operational fifth-generation fighters -- [to] strengthen India's path to an advanced airpower future."

While details are scarce so far, photos of the aircraft had a lot to say.

On Twitter, aviation geeks and enthusiasts noted the advanced features on the heavy weapons load-capable F-16, including triple Advanced Medium-Range Air-to-Air Missile launchers -- meaning it could hold three AMRAAMs per pylon -- and a special, retractable refueling probe. A boom is typically used in F-16 aerial refuelings.

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"The F-21 incorporates several specific capabilities to address the Indian Air Force's unique requirements, including an aerial refueling probe and an upgraded cockpit with a new touchscreen Large Area Display," said Lockheed spokesman John Losinger. The cockpit display would be similar to that in an F-35.

Losinger would not go into additional aircraft details for "competition reasons" but said the F-21 is specifically configured for the Indian Air Force.

Could the U.S. buy into the venture? It doesn’t look like it.

"We are not proposing the F-21 to any other customer" at this time, Losinger said in an email.

In July, the company said it was teaming up with Tata Advanced Systems to make a more advanced aircraft to compete for India's 114-jet requirement, or what Lockheed views as a $15 billion export potential.

The company is competing against Boeing's F/A-18 Super Hornet, Saab's Gripen, Dassault Aviation's Rafale, the Eurofighter Typhoon and a Russian aircraft -- potentially its Su-57 stealth jet project -- for the contract, according to Reuters.

Last year, Lockheed secured a $1.12 billion contract to deliver its latest F-16V Block 70 jet, which currently stands as most advanced version of the venerable fourth-generation fighter, to the Royal Bahraini Air Force. The U.S. State Department approved the foreign military sale in 2017.

The F-16V, known as the Viper, encompasses advanced active electronically scanned array (AESA) radars and provides air-to-ground capabilities much like the F-22 and F-35, Lockheed said at the time.

In 2017, Lockheed officials told DefenseOne that the company plans to move its F-16 production line to South Carolina from Fort Worth, Texas -- where it built the single-engine fighters for more than 40 years -- to make room for F-35 production.

-- Oriana Pawlyk can be reached at oriana.pawlyk@military.com. Follow her on Twitter at @Oriana0214.