The Air Force is years away from making a decision whether to reduce the number of F-35s it plans to purchase.Air Combat Command (ACC) chief Gen. Herbert “Hawk” Carlisle said Tuesday the Air Force would be in a better position to decide how many conventional F-35A variants it would purchase when it reaches full operational capability (FOC). Air Force spokeswoman Maj. Kelley Jeter said Tuesday the service is slated to reach FOC by 2018.“I think there is a decision to…