Gabrielle Union joined an EXCLUSIVE mile-high club this week ... becoming maybe the first wife ever to watch her hubby hit a game-winning shot on an airplane!!!
It all went down Wednesday night ... when Gabby was some 30,000 feet in the air watching Dwayne Wade's Heat play the Warriors.
Union says the plane had Wi-Fi, so she was able to catch the whole game ... including Wade's miracle buzzer beater that lifted Miami over Golden State, 126-125.
D-WADE FOR THE WIN! ud83dude31 pic.twitter.com/rjpRdIn4wG
— NBA on TNT (@NBAonTNT) February 28, 2019
Union tells TMZ Sports her reaction to the play was priceless .