TMZ Hip Hop obtained footage of Flav trying not to pop his top Thursday night at a Spirit gate inside Harry Reid International Airport. Sources tell us it was around 11:30 PM, and the iconic Public Enemy rapper was sitting near the gate waiting to catch a flight to Detroit.

We're told he was working on his laptop and chatting on the phone -- basically, preoccupied -- when he noticed the gate agent shutting the jetway door. He ran up, but she wouldn't reopen it for him ... so he missed the flight.

You can see he was super annoyed, and argued back and forth with the Spirit employee -- another man even stepped in to plead Flav's case.

Flav was fired up and hurled some obscenities at the employee, who threatened to call security -- but thankfully for Flav, in the end, she didn't and he did not become public enemy #1 at the Vegas airport.

Sources close to Flav tell us he commonly waits to board after everyone else because people want to take pictures with him ... and he doesn't want to hold up the boarding process. Those sources also claim Spirit actually did reopen the door to let other passengers in -- before this video starts -- but closed it again on Flav and 2 other people.

Flav tells TMZ ... "Spirit Airlines shut the door on me while I was in line to board. I was upset and said some harsh words to the gate agent. I apologize to those who witnessed me acting out of character. I do not apologize to Spirit Airlines or the gate agent."

Vanilla Ice also had a similar meltdown after missing a flight a few years ago, and as we reported ... Gillie Da Kid just had an intense showdown with a TSA agent.