Image source: U.S. Air National Guard photo by Staff Sgt. William Hopper.

According to the U.S. Air Force, it costs anywhere from $700 million to $840 million per year to operate and maintain America's fleet of 300-odd A-10 Warthog bombers. The U.S. Government Accountability Office says USAF overstates the case, but if that number is accurate, the Air Force could skip hiring Boeing (NYSE:BA) to replace the wings on a lot of A-10s, and quit paying Northrop Grumman (NYSE:NOC) to maintain them -- in order to save enough money to buy seven or eight of Lockheed Martin's (NYSE:LMT) shiny new F-35 fighter jets instead. So is the U.S. Air Force right about that?

Figuring out how much a warplane costs to buy is pretty easy. Every time the Air Force buys one, that information -- the plane purchased, whether it's Northrop Grumman, Boeing, or Lockheed Martin that builds it, and how much they charge -- gets published almost immediately on the Pentagon's daily list of contract awards. But figuring out the cost of maintaining and flying those planes day to day? Determining which weapons are most cost-effective, such that the companies that make them are likely to win more business from the Pentagon? That's all a bit trickier.

In fact, this information is so hard to come by that last year, I filed a Freedom of Information Act (FOIA) request with the U.S. Air Force to get some answers. What I received in response was a pages-long printout showing:

  • every active aircraft in the U.S. Air Force arsenal
  • the number of hours they flew in 2014 (the most recent full year for which data was available)
  • their cost to operate, including everything from maintenance costs to fuel costs to pilot salaries, and
  • for easier apples-to-apples comparison, their "ownership cost per flight hour," including the cost of any repairs or upgrades made to the aircraft during the year.

Parsing all of this information is going to take some time, but this is the kind of information that investors in Northrop Grumman, Boeing, and Lockheed Martin require when making their investment decisions. Rest assured that we're working our way through the data.

And to start the process, let's go through a quick rundown of the top 10 most expensive aircraft (to fly) in the U.S. Air Force arsenal, which company makes them -- and what implications this data holds for investors.

Introducing the U.S. Air Force's Top 10 Priciest Planes (to Fly) from The Motley Fool.