Didn't the ATC Vigi and Viking fleets find a nice simple solution in the shape of dayglo stripes on the wings? Surely thats a nice, simple and cheap immediate fix to help with visibility?
Yes....But.... the panels are not as bright as the old dayglo colours and from a distance look a 'browny' colour so can act almost like camouflage by breaking up the outline(depending on background colour).
The colour/darkness/size/positioning of any hi visibility panels would have to be cleared by the Aircraft Design Authority for structural temperature reasons.
It is as simple as
White = cold
Black = Hot
Red = Hot
The temperature difference between white and red is considerable.