Annual Sales $3.9 billion

Rank 4th (Revenue between $1-5 billion)

Average Five-Year Score Improvement n.a.

Spirit has a brief history as a company, having been spun off by Boeing in 2005 to Onex Corp., a private equity firm that took it public. The underutilized and underperforming operation was radically transformed by Onex, which has focused on cost efficiencies and supply-chain management to build the business. That was on display late last year when Spirit made the disappointing but disciplined decision not to acquire Airbus production facilities in Europe.