From what I could find the last time that a new Air Force One was replaced was in 2015 and before that 25 years. Why does Don the Con think he needs a new one if they are only 3 years old?
Actually, they were ordered by Obama. When Trump took office, he renegotiated the contract. They have not been replaced after 3 years service, as you said.
US Air Force, Boeing begin work on new Air Force One Laurent Barthelemy , AFP•February 2, 2016