Business Insider recently toured the factory, officially called Air Force Plant 4. An overhead view of the production line, looking from right to left, reveals the tremendous scale of the operation.

‘This is about bringing the T into the 21st century’: Gov. Baker sees first rail cars roll off Springfield factory line. Updated: Dec. 18, 2018, 5:38 p.m.

Lockheed Martin's F-35 Lightning II is one of the world's most advanced fighter jets. Business Insider toured a facility where the stealth jet is made. The production line in Fort Worth, Texas, is ...