It's all over but the crying now, folks. On Jan. 3, the Navy's deadline for submitting bids to build its next-generation, carrier-capable "MQ-25 Stingray" drone aerial refueling tanker came due. Who will win?

That's an excellent question, the answer to which will determine which defense contractor wins a contract that could be valued in the billions.

Boeing MQ-25 prototype, on the ground

Image source: Boeing.

And then there were three

Back when this competition began, the Navy invited four big defense contractors to bid to build its new carrier refueling drone -- designed to safely deliver jet fuel to fighters in flight, extending the range of the Navy's F/A-18 Super Hornets and EA-18G Growlers. Privately held General Atomics, plus publicly traded Boeing (NYSE:BA)Lockheed Martin (NYSE:LMT), and Northrop Grumman (NYSE:NOC) were all expected to bid.

Initially, my money was on Northrop Grumman to win with a variant of its X-47B carrier drone. Instead, Northrop Grumman dropped out of the MQ-25 competition in October, leaving three companies in the race. That same month, though, Boeing and Lockheed released concept art on their respective MQ-25 prototype offerings (albeit art showing little more than a refueling pod attached to some type of aircraft, of indeterminate form). And General Atomics released an artist's conception of a fully formed tanker drone (one closely resembling its Sea Avenger drone in design).

Last month, Boeing went one step further, and pulled the curtain off an actual prototype MQ-25 (pictured above). In contrast to General Atomics, which has so far only shown artwork, and Lockheed Martin -- which hasn't even released a picture of an entire plane, Boeing says its drone prototype is already "ready," to fly, albeit it hasn't yet been flight-tested. A report from The Drive's military tech website The War Zone says that Boeing plans to "finish engine test runs on the ground" and then begin "deck handling demonstrations in early 2018."

Touting its experience building Hornets and Growlers for the Navy "seamlessly integrate[d] with a carrier's catapult and launch and recovery systems," Boeing argues its version of MQ-25 "is the unmanned aircraft system (UAS) best suited for refueling U.S. Navy jets operating from aircraft carriers." (And Boeing should know. They already build refueling airplanes for the Air Force.)

That said, the mil-tech experts at FoxtrotAlpha are still giving General Atomics the upper hand in this competition. According to that website, GA's "Avenger" design (on which GA's version of the MQ-25 appears to be based) offers "a no-nonsense cost effective tool that has incrementally outclassed most of its peers when it comes to adaptability, reliability, cost-effectiveness and systems integration." FoxtrotAlpha predicts GA's bid will "probably [be] a fraction of the cost of [that of] its high-end competitors."

And of course, we have yet to see what marvel Lockheed Martin's famed (and famously secretive) Skunk Works division will produce to challenge Boeing and GA.

What it all means for investors

The Navy is reportedly envisioning an eventual purchase of up to 72 MQ-25 tanker drones for its aircraft carriers, breaking down into flights of one "system" of four drones for each of nine aircraft carrier air wings (36 drones total), and one backup system per each air wing (so another 36 drones). The first contract will be for one complete system, i.e., four drones, plus a control station and any engineering modifications needed to be made to the host aircraft carrier to accommodate the drones.

Price-wise, the Government Accountability Office notes that the Navy has budgeted "almost $2.5 billion" for MQ-25 development from 2017 through 2022. Once actual production begins, though, that number could rise. When Northrop Grumman built its two X-47B carrier drone prototypes (a test-bed preceding development of MQ-25) for the Navy a few years ago, those cost $744 million total. Should the MQ-25 carry a similar price tag, it's conceivable that a full contract for the production of 72 drone aircraft could cost taxpayers as much as $26.8 billion.

We should get a better handle on that figure, though, when a winner is chosen this summer. Once that happens, you can expect a swift update from The Motley Fool.

Rich Smith has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.