Not running emissions equipment on modern diesel military equipment is a tacit admission of the unreliability (and added expense) that us mere consumers are required to bear, all to 'save the planet' of course. You could use the argument that the military doesn't use an SCR (DEF) system on their diesel equipment because of the possibility of not being able to get DEF in remote areas and having the vehicle shut down. However, argument doesn't hold true for other emissions systems such as a DPF or cooled EGR, which military vehicles also lack. Neither the EGR nor the DPF systems improve engine performance, they strictly are in place to control emissions but have the downside of creating serious reliability problems, which is of course why the military doesn't use them. I've heard sworn testimony from current top-level ranking military leaders that the biggest threat the US faces isn't foreign enemies, but rather is "climate change." The hypocrisy is rich, given if that really were the case, the military is not utilizing these longstanding diesel engine emissions controls devices. And you are 100% correct on aircraft emissions as well.