why so expensive?
Phil is correct.
The capital cost of the helicopter is so much higher than the capital cost of an aeroplane.
Hence the standing overheads are proportionally and significantly higher.
Then the facts of low utilisation and high maintenance costs ensure that it has to be expensive to charter.
Also, the cruise speed in a 4/6 seat helicopter is (typically) MUCH slower than a 4 or 6 seater aeroplane, so the cost per mile is exponentially higher in a rotary.
And after all that, you've got the agents commission and the operators profit.
Usually the agent is the one that makes the money!
(and no, I'm not one.....)
Big Ls