Mmmh.... i note similar issue too, units seems to have diferent behaviour in campaign than in single missions. May be due to crew efficience used ?
1]
Are you sure the plane is equiped with radar ? Or simply the icon has the circle and thats all, no radar mounted ?
2]
Aspect ratio, fog, waves can affect the planes capability.
3]
There is a line affecting the stricke probability, reducing stricke probability we do not reduce the planes quantity, we reduce the probability of detection and attack when the plane is on detection range... planes will meet us the same frecuent, but will not attack us, (not sure, may be i am wrong, but i remember that from SH III) try increasing stricke probability and sure it will attack you with no dude.
Many thanks for your jobs and effort...
