The F-35 Joint Strike Fighter's concurrency cost estimates have dropped slightly since 2013, from $1.7 billion to $1.6 billion, according to a report obtained this week by InsideDefense.com. The report, published in April , attributes the slight drop to the resolution of issues the F-35 joint program office forecasted the program would face in low-rate initial production Lots 4-6 as well as efforts by prime contractor Lockheed Martin to quickly introduce production line changes, reducing the number of necessary...