He WANTED to sign with ADIDAS IN 1984 ... but they didn't want to make him a priority.

TALK ABOUT A BILLION DOLLAR MISTAKE!!!

MJ explained the whole thing in episode 5 of "The Last Dance" ... admitting his mom FORCED him get on a plane and take a pitch meeting with the Swoosh just to hear what they had to say.

"My mother said, 'You're gonna go listen. You may not like it, but you're gonna go listen,'" Jordan said ... "She made me get on that plane and go listen."

At the time, MJ thought Nikes just weren't a top-flight shoe. He was more into the Adidas.

But, when a very young MJ met with Adidas, they made it clear he would NOT be pushed as their premiere athlete and they weren't open to giving him his own shoe.

Converse -- the other top sneaker company at the time -- had Magic Johnson and Larry Bird on their roster and also didn't see him as their top guy.

So, Jordan took the Nike meeting -- and the rest is history.

"Go into that meeting not wanting to be there, and Nike made this big pitch," Jordan said ... "My father said, 'You'd have to be a fool not taking this deal. This is the best deal.'"

Nike was working on their "Air" technology -- which they built into MJ's shoe and called "Air Jordan."

Also, Nike hired Spike Lee to direct the Air Jordan commercials -- and they were AWESOME.

In fact, Nike only expected $3 million in sales in the first 4 years ... but it sold $126 million in the first year alone!!!

Jordans ultimately became the most popular shoe in the world and made Michael hundreds of millions of dollars over the years.