As to which platform is more profitable that depends on your app and on the market you’re targeting.
There’s pros and cons either way.
If you wish to deploy an app quickly, Android is the choice.
If most of your market (users) is Android, well . . .
If you already have an Android device and a windows computer . . .
If you . . .
I’ve found that there’s a need to be able to build for both platforms (Windows mobile?) because the market is not just one market, or two markets, but it’s two tightly inter-woven markets.
If I have a cool app than I wish to display, way too often I hear, “Will it work with iOS?”
So to have a truly successfull Android app I’m going to need a companion iOS app.
So, should you start with Android or iOS?
We all start at different points, so your path will be different from mine.