The F-35 Lightning II, also known as the Joint Strike Fighter (JSF), is the Dept. of Defense¿s (DoD) most costly and ambitious aircraft acquisition, seeking to simultaneously develop and field three aircraft variants for the Air Force, Navy, Marine Corps, and eight international partners. The JSF is critical for recapitalizing tactical air forces and will require a long-term commitment to very large annual funding outlays. The current estimated investment is $382 billion to develop and procure 2,457 aircraft. This report discusses: (1) program cost and schedule changes and their implications on affordability; (2) progress made during 2010; (3) design and manufacturing maturity; and (4) test plans and progress. Charts and tables. This is a print on demand report.