While the U.S. Air Force remains below a fiscal 2018 National Defense Authorization Act enacted floor of 1,145 Primary Aircraft Inventory (PMAI) fighters, a new 10-year fighter force structure study raises hopes, according to Rep. Robert Wittman (R-Va.), the chairman of the House Armed Services Committee's Tactical Air and Land Forces panel. Air Force Secretary Troy Meink signed the 24-page Long Term USAF Fighter Force Structure report delivered to Congress last month (Defense Daily, Oct. 30). Mandated under Section 142…