In the UK police ops are managed according to the Police Air Ops Manual. It is a CAA publication: CAP 612. There is half a page on police dog ops in there. Available from the UK CAA website:
The UK Civil Aviation Authority
They say dogs are most comfortable if they cannot see the view.......
No they don't!
They say; Sect5 Chap2 Para 6.1b
Note: There is no requirement for the animal to lie down. Dogs are more at ease when able to see out the window.