I have the same exact issue, and know what is causing it: the fact that you are using the .ts extension. When I use app.js (and all .js extensions) then my app runs sound.
However, I cannot find a way to allow ionic to compile .ts files properly. This is very important, mainly to my IDE (webstorm) and being able to show errors/warnings etc. Typescript compiler doesn't work and there are red squigglys everywhere because webstorm is thinking it is javascript, not typescript.
Any ideas on how to get Ionic to play well with .ts files?