There are many US movies that involve military themes that are made with the assistance of the US military. It's not surprising that the US military chooses which films it works with. So, if you want a US aircraft carrier in your film you're going to either use CGI (relatively recently available for most films) or you're going to use a script that doesn't show the US in a bad light.

This isn't overt propaganda in the traditional sense, but the effect is the same.