There's nothing like America's most expensive weapons system ever

America's most expensive weapons system ever built is on track for "initial combat use" by September 2016.

The $400 billion and counting F-35 program has so far delivered 140 of the anticipated 2,443 jets to the US Department of Defense and five aircraft to foreign military buyers.

Here is a look at the unique capabilities of the F-35 variant aircraft:

The lightest of the jets is the F-35A:

The F-35B is in the middle at 14.3 feet tall and weighs 32,300 pounds.

The F-35C is the tallest and the heaviest:

The F-35A and F-35B have the same wingspan and nearly the same length:

Designed for the Navy, the F-35C features longer wings to create drag for the jet to slowly land on aircraft carriers:

The F-35C has another unique wing design:

The F-35A is the only variant aircraft that has an internal gun; aside from that, the jets have similar designs:

All three variants are coated with a special material to avoid radar:

The F-35's have serious fire power:

The F-35C carries 19,750 pounds of fuel, the most fuel of the variant aircraft. All jets have the capability to be refueled in air:

The F-35A is refueled differently:

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