Have you heard? There's a $50 billion Air Force contract up for grabs -- and America's biggest defense contractors are forming battle lines to try to win it.

Sometime next year, the Air Force's "T-X" trainer contract will begin, and one lucky company will win an $8.4 billion award to build 350 new trainers -- high-performance jet aircraft designed to mimic the performance of even higher-performance fighter jets. Ultimately, experts estimate as many as 1,000 T-X trainers may be sold. And when you factor in the cost of maintenance and upgrades for this fleet over a period of 50 years, the total value could reach as high as $50 billion.

But who will win the loot?

Perhaps anticipating a quick victory, Boeing has already named its new training jet the "Boeing T-X." Image source: Boeing.

So far, five industry teams have tossed their hats in the ring -- and more may do so. Last week, Textron (NYSE:TXT), which built its Scorpion jet partly in anticipation of bidding for T-X, affirmed that it's monitoring the competition's "progress" with an eye to making a bid. If it does ultimately bid, though, Textron will face stiff competition. Here are the teams, as they currently stand:

Boeing (NYSE:BA)

Boeing has already unveiled its offering, optimistically named the "Boeing T-X." Built in cooperation with Saab, the plane features a single engine and twin "tails" (vertical stabilizers), similar to Lockheed Martin's F-35 design. Boeing announced that the first of two "production-ready" Boeing T-X jets completed a flight in St. Louis last week. The second prototype is expected to begin flying in early 2017.

Raytheon (NYSE:RTN)

Raytheon is bidding a T-100 training jet in cooperation with Italy's Leonardo (nee Finmeccanica), which actually builds the plane. Leonardo had previously partnered with General Dynamics as prime contractor, but General Dynamics pulled out of the competition last year -- giving Raytheon an opportunity to enter the competition. The companies' design features twin engines (as in the Lockheed-designed F-22), but only a single vertical stabilizer -- more resembling a fourth-generation F-16's design than the fifth-generation F-22.

Lockheed Martin (NYSE:LMT)

Lockheed Martin, which builds both of the fifth-generation fighter jets that new pilots will train on the T-X to fly, has teamed up with longtime partner Korea Aerospace Industries. Together, they will offer a variant of their jointly developed T-50 Golden Eagle training jet to become the new T-X trainer.

Lockheed boasts that its T-50A trainer "is purpose-built around 5th Generation thinking" that went into making the F-22 Raptor and F-35 Lightning II, featuring "advanced capabilities that have never been available before." Strangely, though, in form Lockheed's T-50A more resembles an F-16 than an F-22 or F-35, having a single engine and a single vertical stabilizer.

Northrop Grumman (NYSE:NOC)

Northrop Grumman built the T-38 Talon trainer jet that currently serves as the Air Force's primary trainer. The incumbent in this competition, Northrop is teaming up with BAE Systems and L-3 Communications. It's been building trainers for 50 years now, and would dearly like to win another five decades worth of revenue from the Air Force. Little is known about its offering at this time, but photos of the aircraft show that it has a single engine (with twin inlets) and a single vertical stabilizer.

Northrop has already succeeded in winning the Air Force's B-21 bomber contract, which on the one hand may be evidence of the faith the Air Force has in its products. On the other hand, if the Air Force's intention is to "spread the wealth" around among several equally capable contractors, then Northrop's win on B-21 may argue against giving it the T-X contract as well.

Sierra Nevada Corp (no, not the beer company)

Last but not least, privately held Sierra Nevada Corp. put in a last minute expression of interest earlier this month. Working in cooperation with Turkish Aerospace Industries, Sierra Nevada aims to offer a "Freedom Trainer" as its entrant into T-X. Sierra Nevada appears to be taking its cue from the F-22, and is building a jet with twin tails and twin engines.

And then there were six?

And now Textron may join the field. Can it win? Well, the Air Force is hoping to use T-X to prepare pilots to fly stealthy F-35 and F-22 fighter jets -- fifth generation jets that will become the future of the Air Force as it begins retiring its non-stealthy fourth-generation F-15s and F-16s.

Textron, Boeing, and Sierra Nevada are all offering jets featuring twin vertical stabilizers, such as are found on the F-35 and F-22. From a cosmetic viewpoint, this suggests that these three firms are starting off with offerings closest to what the Air Force may be looking for. Textron's and Sierra Nevada's twin-engine designs, however, appear to be better suited for training pilots to fly the Air Force's older F-22 Raptor jets, while Boeing is better at mimicking the F-35 -- which, in time, will be by far the more common aircraft model.

At this point, therefore, I have to give the advantage on this contract to Boeing.

Farther down the line, it will be important to judge the acceleration that the aircraft can endure. (The Air Force is looking for a plane that can endure G-forces of 6.5 to 7.5). Additionally, Aviation Week points out that the quality of the bidders' ground-based training systems -- the flight simulators -- will weigh heavily on the Air Force's decision.

And then, of course, there's price. We simply don't know at this point how much any of these planes will cost. For a budget-constrained Air Force, that could be the factor that finally determines who wins and who loses T-X.