Amber Phillips stepped on an American Airlines flight from Raleigh-Durham to Washington on Thursday evening and immediately noticed how small the plane was. There were 65 seats, just two in each row.

When Phillips sat down, her arm rested next to that of the passenger in the adjacent seat, she said. Their arms were touching.

“I was thinking, I really hope she doesn’t treat me mean,” said Phillips, 28, who lives in Washington. “She was fidgeting, and finally she looks at me and goes, ‘Can you move over?’ ”

Phillips told her: “No, I actually can’t. I’m in the window seat.”

Phillips said she noticed the woman was growing increasingly annoyed at the tight space they were in.

“I wasn’t going to say anything because I know how hard it is for people who are perceived as fat to say, ‘I was mistreated,’ ” said Phillips, who shared her experience in a series of viral tweets, including one that said, “The cops were called on me for flying while fat & Black.”

But soon, Phillips decided not to hold her tongue. As the flight progressed, the woman rested her ankle on her own her knee, so the bottom of her foot was facing Phillips, she said.

Phillips said she felt that the woman was trying to push her closer to the window.

“I said, ‘you’re being awful, don’t let the bottom of your foot touch me,’ ” Phillips said.

The woman, Phillips said, responded.

“She turned my words and said I was being mean,” said Phillips, co-host of the podcast “The Black Joy Mixtape.”

Things were tense.

“The whole time I was sitting there I was trying not to cry,” Phillips said. “I dropped my headphones, and I was afraid to pick them up.”

Phillips said she then grabbed her cellphone and started recording the woman on the plane. The woman tried to block her face from Phillips’s camera. Then the woman complained to a flight attendant about Phillips, she said.

They got off the plane at Reagan National Airport and headed to a shuttle bus that would bring them to a terminal.

Phillips said she was surprised moments later when a flight attendant announced that she was calling the police.

An officer with the Metropolitan Washington Airports Authority Police arrived and approached Phillips and told her to get off the shuttle, she said. He told her he was called for an assault investigation and asked her some questions. After a few minutes, the officer told both Phillips and the other woman they could leave. The incident delayed Phillips about 30 minutes, she said.

“All of this because my arm was touching this woman,” Phillips said.

The Washington Post could not locate the woman or identify her. Neither the airline, nor the police who were eventually called, would release her name.

In a news release American Airlines said: “Two passengers seated next to each other engaged in a verbal altercation while on board. Upon landing in DCA shortly after 8 p.m. ET, one of the passengers requested the flight attendant contact law enforcement.”

Airline spokeswoman Kristen Foster said that American employees had “an obligation” to call the police. “We contacted law enforcement at the request of another passenger on the flight,” she said in an email. “We have an obligation to contact law enforcement if any passenger requests it (just as we would if someone requested medical assistance, for example).”

MWAA police said they were called because of an “in-flight incident.”

“Assistance was requested following an in-flight incident involving two passengers, which continued on an American Airlines shuttle bus at Reagan National Airport. … Both passengers complied with police requests and it was determined that there was no immediate threat to passenger safety. There were no arrests, no charges were filed and both passengers continued on their way.”

Phillips said she was scared, upset and shaken.

“White people literally need to stop calling the cops on black people who make them uncomfortable,” she said. “They’re calling the cops like they need to speak to the manager or something. You’re not allowed to call the cops for things that aren’t true.”

Video posted on Twitter shows police using a stun gun on a passenger aboard a Chicago-bound American Airlines flight at Miami International Airport on April 22. (PoleVaultDream/Twitter)