Market Garden - Air Interdiction

[ebitt]

I have been trying Gary Cobleigh's excellent scenario of the campaign with additional forces and I seem to be having a problem with Air Interdiction. The parameter file (PDT) lists 0 (zero) for the German Air Interdiction, but virtually any time a unit with vehicles moves it seems to take losses. It's a long way from Joe's Bridge to Arnhem and these units are decimated by the time they pass Eindhoven. Should units in travel mode but not in contact with enemy forces take losses just by moving?

Thanks

Ed