There are more Boeing 737s flying in the skies of Earth today than any other model of commercial air transport. Back in 2000, to keep up with demand, the company began producing 737s at the then record rate of 1 per day, or rather, 30 per month. Ten years later, the company was producing 737's at a rate of 31.5 per month.
At that point in 2010, the company's orders were finally strong enough to justify speeding things up. By 2014, the company was producing 737s at a rate of 42 per month and now has plans to increase its production rate further with the goal of delivering 47 per month in 2017 and possibly as many as 52 per month in 2018.
The YouTube video below reveals some insights into how Boeing's mechanics do it.
To get an idea of how much the video has been speeded up, the assembly line shown after the wings are attached to the fuselage, where 737s are "flying" down the factory floor in single file, moves forward at a continuous rate of two inches per minute.
Altogether, the production of a Boeing 737 represents anywhere from 367,000 to 600,000 individual parts (depending on the exact model) that are assembled to fly together in close formation.