Is it possible to do AOT compilation in Angular using only ES5?

More to the point, can I use the [NGTools Webpack plugin](https://github.com/angular/angular-cli/tree/master/packages/%40ngtools/webpack) with ES5?

I know TypeScript is the preferable language of choice for Angular, however my place of employment did not approve using TypeScript for our Angular project. My hands are a bit tied, and I don't want performance to suffer on the client due to this.

**Some relevant info on my project:**

* Webpack 2 for build/packaging
* Written in ES2015 transpiled to ES5 using Babel

I have looked all over and have not been able to find a clear answer on this, I would really appreciate any info anyone can provide.

Thanks in advance!