Marlon Wayans says he's not to blame for missing his upcoming show after an issue with United Airlines, but apparently, the cops think differently ... because he's been hit with a citation for the incident.

A spokesperson for the Denver PD tells us Wayans got into it with a gate agent for the airline Friday as he was trying to fly out of the Mile High City. Cops say they spoke to all parties involved -- including Wayans -- and slapped him with a citation for disturbing the peace.

We spoke with a witness who tells us Wayans was pissed he had to check a bag during boarding, allegedly slamming his ticket on the counter and then proceeding to board the plane. The witness says the gate agent tried to stop Wayans, but he couldn't, so he called security.

However, a source close to Marlon says he was first told he had to consolidate his bag and then being told he had to check the bag altogether.

We're told about 30 minutes later, Wayans was escorted off the plane ... and that's the time when cops got involved. We got video of Marlon leaving the ticketing counter looking pissed.

As for Marlon, he took to Twitter to air his grievances with the airline, tweeting, "If this is how United treats their first class customers.... I'd rather fly any competitor coach. Sorry KC I'm gonna miss tonight's shows due to a United gate agent who probably hated white chicks."

For those not following along, "White Chicks" is a movie he and his brother, Shawn, starred in back in 2004.

Marlon, who was set to perform Friday night at Kansas City Improv, says the whole ordeal has forced him to miss his show, writing, "It's not my fault blame the gate agent and United Airlines can't believe how they allow their first class customers to be treated this way. I need corporate to reach out DM me. this agent was rude."

A source tells us Marlon was eventually able to get out of Denver on another airline.