Flight Distance Calculator Time Duration Estimator

Would be great if 1) there was an options for distance in miles, and 2) you could search by airport code instead of the full city name

I have been doing distance calculations manually for years. I am happy to finally have an app that can show me distances automatically. I have not yet seen if I can convert from KM to miles, would like to suggest this is important (for Americans anyways). I went Premium for 99 cents and I get the map. Please add a selector for units between metric and imperial if you would or please point me to how to do this if it already exists