Noggin, if the aeroplane does not belong to your company then there is no problem putting the rental costs etc through as buisness expenses.
The problem arises when your company owns the aeroplane. If there is only one director then the aeroplane is regarded in the same light as a company car and you can incur horrendous benefit in kind charges. They can technically do this even if the aircraft is rented out although their case becomes much weaker in appeal if this is the case.
My accountant's solution was simple. Either have two directors so then the aeroplane is treated as a pool vehicle and insurs no benefit in kind or, have two aeroplanes so that neither is wholly allocated to the director as a personal vehicle.
I wish I could have afforded the 2nd option but common sense eventually prevailed
