Queen Obioma accused the airline of discriminating against her because she is black, Nigerian and African.
Obioma said she and her two kids were travelling from Lagos, Nigeria, to Ontario, Canada, on March 4, 2016, when an airline employee escorted her off the plane before take-off.
She shortly after found that a passenger complained that she smelled "pungent" (a strong smell).
In the civil right lawsuit, Obioma accused the airline of discriminating against her because she is black, Nigerian and African.
According to the suit, she said the drama started when she and her kids boarded the flight at Bush Intercontinental Airport in Houston, United States, after completing the longest leg of their trip from Lagos.
Obioma said a white man was already sitting in her assigned seat in business class when she got there.
She said the man refused to get up despite the intervention of the flight staff. So she agreed to sit in the nearby seat assigned to the man.
Before takeoff, Obioma said she went to the bathroom and when she tried to return to her seat, the same white man blocked her path.
She said one of the Airlines staff then ordered her to get off the plane.
Another United Airlines employee was said to have told Obioma that the pilot received a complaint from the man sitting near her that she smelled 'pungent'.
According to her, the family was travelling from Houston to San Francisco where they were going to take a connecting flight to Canada.