9. L-3 Communications (LLL) -- electronics Arm sales: $12.5 billion, total sales: $15.2 billion Gross profit: $956 million, total workforce: 61,000 Some 83% of L-3 Communications sales in 2011 came from arms sales, but this was down from what it sold the prior year. The company has four business segments: electronic systems; aircraft modernization and maintenance; national security solutions; and command, control, communications, intelligence, surveillance and reconnaissance. Among many products manufactured, the company has become a major provider of unmanned aircraft systems.