for offshore it was 8-9% net profit in the boom years, 2000-2014 during the high oil price period, now most offshore operators are losing money. Air medical companies make very high margins 10-17%. Charter companies, utility operators, tours operators make somewhere between 4-6% net profit. How do I know this? I'm a market research geek with access to specialized industry reports. I have this one report on 200 privately held European helicopter operators. I can get information for profit, company value, revenue growth etc.
Plimsoll reports
IBIS world
Technavio
these are good places to get this info