What are Mr Putin's term limits? Suggest you look at his entire history at the top of government, to include the Medvedev interregnum. We know what the American ones are. The comparison is not apples to apples.
Jimmy Carter once declared that he'd close Camp David, as it was an excess or a luxury. Once he got into office, the light went on and Camp David remains open to this day. Perhaps once in the job Donald Trump will likewise see things differently.
Your point on the 747 being outdated: perhaps, but the other face of the same coin is that it is mature technology and has 4 donks. There are some stringent rules on how reliable, how mature, and how well proven a particular plane can be to be eligible for Presidential service. Others probably know the details, and will hopefully elaborate.