TM,
There can't be a huge downwards effect on prices as most of the costs involved in ac are fixed, including lease rates. The leasing companies do not change their rates when times are bad. It's no different from normal asset financing.
For the lucky guys at Bristow who own more of their ac than say CHC, they might be able to fiddle with their returns and reduce their prices. For operators operating on a financed fleet, the returns might not stack up if they lower their charges to clients. (note other operators are available..!)
There will be price deflation of course (the race for a smaller barrel of business will see to that) but I think 20% is a bit ambitious and unrealisitic. I'd love to be there when oil goes back up to $100 a barrell when the big RW operators ask for their returns to go back up....!