Heres a pic of a red shirt I found online. Ill take some pics of the black Tee I found tonight.
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Just in looking at it, and also having the knowledge of being pretty familiar with the official Nike apparel line as a young teen in 89 and 90, I don't think this red shirt in the picture is legit.
For one, the majority of t-shirts and sweatshirts that I've seen from the late 80s-early 90s that are known to be absolutely legit have the Nike grey tag:
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I just went to my "good" closet where I checked 7 shirts from 1989 and 1990 that I have hanging up together in a line, and every single one had the grey tag.
That's not to say ALL legit shirts had it, because there are always exceptions. Many people cut out the tags back then. And then I've also seen a few pop up here and there that were 100% legit designs but on Fruit of the Loom brand shirts. It's possible that Nike could have occasionally used shirt stock from other companies from time to time back then. For what reason, I don't know. But it's possible.
But the other big problem with this shirt is the total absence of any Nike branding. Back then, there was no Brand Jordan entity. The Swoosh and the Jumpman were basically inseparable on all Jordan apparel. Even if there wasn't a Swoosh in the design, which in pretty much every case there was, the shirt itself would have almost certainly been branded in some way as a Nike shirt. Nike always wanted respeck on their name. LOL.
Based on the trademark on the shirt, it's definitely from 1990. But as far as I know there was no line called "Flight 23" put out by Nike. I do know that for basketball shoes in 89-90, Nike had a Flight line and a Force line, which many of their catalogs outlined. But not "Flight 23." The AJ IV and AJ V (and I believe maybe even the AJ VI) were considered part of the Flight line, but I think that changed around or after the VI in 1991 and the Air Jordan began to be considered "its own thing" at that point. Rarely acknowledged fact - THAT'S the true genesis of Brand Jordan, even if they didn't officially incorporate it until 1997. Between the VI and VII, that's when they decided to see what it would be like to see a Jordan shoe stand on its own without a Swoosh, and lo and behold the VII came along with no Swoosh. But I digress.
Yet another thing to consider is that back then, it was easier to get away with making and distributing knock offs. It probably wouldn't have been as difficult to print your own shirts and designs and maybe get them into a local mom and pop. Or hock them outside Chicago Stadium on game nights. I STILL see a dozen counterfeiters do that crap at any given Raiders game.
Anyway, in my opinion based off of what I know from being around and aware back then, this is a knock off shirt. But if anyone else knows something different, by all means enlighten us.