If you give us some more info we might be able to help you better :) Sandman2 is right about the meds too. Although I'm not a big fan of medicating children -- it does make a difference on their behavior!!
Good point by tgtiffany. Are the wife and you separated? And does he feel this way because he spends most of the time with her? Do his teachers also feel he rules the classroom? Oh, and by the way, in your last example since you were getting home from out of town, I would assume it was later in the day. Is he on meds? When had he taken the last medication? Kids with ADHD act very impulsively. Which was what he did. How you work with ADHD kids is very different then how you work with regular kids. And yes, the way it would have been dealt with when you were a kid, definitely would not help an ADHD child. I suggest that you get the book, "The ADD/ ADHD Answer book," by Susan Ashley. You will find lots of good suggestions on how to work with him. And if you and your wife are separated it does add another layer to the problem.
Wow. Crazy. So I take it that you have custody of him? Or just visitation? Cause it matters a lot. But of course regardless he needs to listen to you as well as his mother!...wait, sorry, just re-read your post and you're still married. Sorry! Are y'all separated? Or is she there during these 'tantrums'? There's way more information needed to help you with this! Feel free to post here or message me if you'd like :) Major is psychology so I know I'm young, but can probably help at least somewhat :)