Farrah Abraham got into a heated exchange with an airport employee today ... which she claims only ended after airport cops showed up ... and get this, it was all over an over-sized duffel bag.
The "Teen Mom" tells TMZ ... she showed up to LAX hours ago with an extra large carry-on bag -- but was informed by American Airlines personnel she couldn't go through security until she checked the bag.
Farrah says she agreed, but says the woman was rude to her regardless, and the two began arguing. That's when Farrah says she told the lady she was acting like "trash" and asked to speak to her supervisor ... but claims the lady called airport police instead.
Farrah says she explained the situation to cops, but they weren't having it and told her to be more respectful. Cooler heads eventually prevailed and Farrah proceeded to make her flight.
The newly-minted porn star tweeted angrily afterwards, "I thought American Airlines was good apparently they need better customer service, never flying with them again:) #CallThePolice."
For what it's worth ...TSA had no record of the incident. We also called American Airlines, but so far no word back.
But here's how it may have looked: