F-35 Lightning II: $122 million
Lockheed Martin's 2001 deal to build these stealth, supersonic fighter jets was at the time the largest military contract ever. The F-35s, intended to replace an aging aircraft arsenal, were developed as part of a Joint Strike Fighter program between the U.S. and its allies and were criticized as underpowered and overweight — and therefore easy targets. Making matters worse, from 2007 to 2008, cyberspies infiltrated the 7.5 million lines of computer code that powered the Joint Strike Fighter, raising concerns that enemies could copy the F-35's design and exploit its weaknesses. In April 2009, Lockheed Martin said it did not believe the program had been compromised.
