To stay ahead in the war for the skies, Boeing chases a simple goal: sell as many 737 jets as it can. Things get more complicated when it comes to building most popular commercial jet ever.

In 2015, the Seattle centenarian pushed an average of 42 per month out of the door and into the sky. By 2018, it aims to make that 52 a month.

Faster assembly requires some fancy new tools, so Boeing brought in the robotic Panel Assembly Line, aka PAL. This 20 foot tall giant glides back and forth on tracks in the floor, patiently and accurately riveting wings together. The 60-ton machine increases production rates by 33 percent, helping workers with all that clamping and drilling.

PAL, built by Washington-based Electroimpact, joins upper and lower skin panels to spars which, like ribs, form the wing's internal support. The lower skin, which will become the bottom of the wing, has a series of "portholes" that airline mechanics use for inspections. Precision matters: These wings aren't just keeping you aloft, they're holding the fuel that's pushing your plane forward.

So the next time you gaze out the window of a 737, remember the helpful PAL who helped you get there.