Is there a KPI to measure average hours flown? I am working on a report for a small charter airline and I want to set a key performance indicator (KPI) to measure average hours flown.

Is there a practice in aviation field to consider optimum flight hours for an airplane? An arbitrary example: Let's say I have a Boeing 767 and I want to consider if that particular model is profitable (I know it depends on payload, routes, and many other things), does it have to make an average 300 hours per month?

Is there such thing in aviation?
I want to set a KPI to measure average hours flown.

You might want to check block hour:


  (aviation) The time from the moment the aircraft door closes at departure of a revenue flight until the moment the aircraft door opens at the arrival gate following its landing. Block hours are the industry-standard measure of aircraft utilization.


(Emphasis mine.)

The Wikipedia article airline cost glossary lists very common terms and KPI's.

One of those terms that could also be applicable to your case (revenue passenger miles) was asked about here: Which aircraft type flies the most annual passenger-miles?