Defensive air-force and garrisoned vs ungarrisoned targets? (Fearless Blue)

OK, I know that if you attack an enemy with your offensive air-force, and that enemy has a direct border with your country, your offensive air-force will be less effective if there are no friendly ground forces nearby. I also know that this does not apply when attacking targets in countries which do not share a common border with your country. However, I want to know if the same thing applies to your DEFENSIVE air-force. I know that your defensive air-force will respond to attacks on targets within your country regardless of whether or not those targets have garrisons, but is the effectiveness of your interceptors / defensive helicopters AFFECTED by whether or not the target which they are defending has a garrison? In other words, does simcountry intentionally make your defensive air-force less effective when defending targets which are ungarrisoned, just like it makes your offensive air-force less effective when attacking targets without ground support? <

Not as far as I know.

I believe the only thing that could potentially reduce your defensive airforce strength is not having any Radar Planes.

Well I was told quite a while ago by a highly accomplished war player that targets do benefit from close by defensive units (didn't specify garrisons, but definitely units).

I personally never really had the chance to verify this, any defensive units I use are busy re-painting or blocking, so its a cant be sure from me...