Australian model Adau Mornyang, convicted in California of assaulting a flight attendant on a Melbourne to Los Angeles journey, has lost her bid for a new trial.

Mornyang faces up to 21 years in US prison when she is sentenced in an LA court next month.

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"Defendant's motion for dismissal of the indictment or, in the alternative, a new trial is denied," US District Court judge Cormac Carney ruled.

The court heard how Mornyang, a 25-year-old from Melbourne, ordered "several glasses of wine" on the January 21 United Airlines flight.

When she was cut off from drinking more, she yelled obscenities and racial slurs, slapped the flight attendant and had to be handcuffed by an air marshal and held at the rear of the plane.

A Los Angeles jury in March found Mornyang guilty of a felony charge of interference with a flight crew member and a misdemeanour count of assault.

Australian model Adau Mornyang. Credit: AAP

On the eve of Mornyang's sentencing, her lawyers argued the judicial district that includes LA was not the proper venue for her trial.

But Judge Carney rejected that.

"Because defendant's interfering conduct began before the slap, and continued over the remainder of the flight, (the) venue was proper in the Central District of California," the judge ruled.

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The model's legal team also argued prosecutors "did not lay proper foundation" to play "an allegedly prejudicial audio recording" of Mornyang at the trial.

The recording was made by another passenger.

Mornyang’s disruptive behaviour occurred during a United Airlines flight. Credit: AP

Judge Carney ruled testimony identifying the audio recording met the "minimum requirements for authentication".

The court heard passengers first began complaining about Mornyang's "erratic behaviour" about 8.5 hours into the flight.

When flight attendant Romeo Gutierrez tried to calm her down she put her left index finger near his face and suddenly "smacked" him.

An air marshal escorted her to the back of the plane and put her in handcuffs.

The judge noted that about two hours before the plane landed in LA, Mornyang was allowed to use the bathroom, but she stayed inside for 45 minutes and would not leave.

Marshals had to carry her out and "while they held her arms and legs, she allegedly kicked" one of the marshals in the chest, the court heard.