Hey Guys

My son is soon to enter the Air Force, and I notice that, as I search the net, I see 2 similar, but not identical, unofficial Air Force Tartans.

I'd like to ask any of you in the USAF, or who know better that I (which is all of you)...

what is the difference?
Which is used by whom?
Why the difference?
Recommendations?

All help gratefully appreciated.