Thanks all for the very comprehensive range of replies!
My situation suggests the plane in question will most likely be part of a non-equity share, although this could change to being an equity share or rented plane.
My company wouldn't reimburse the cost of the plane, aside from maybe the equivalent petrol costs for the journey, however I've no issues taking it on the chin for the extra hours in the air, pleasure, and speed of the journey on the odd occasion it works out.
Obviously very much wx dependant, and I'll always be a position where the car is on the drive should the conditions not be right, although I guess getting back on time should always be a consideration!