A Hawaii woman says she was forced to hold her son on her lap for a three-hour United Airlines flight last week after the company sold his seat to a standby passenger.

Shirley Yamauchi, 42, purchased two tickets for nearly $1,000 each so she and Taizo, her 27-month-old son, could fly together from Hawaii to Boston, where she was attending a teacher conference. United Airlines policy requires passengers above the age of 2 to fly in their own seats.

Yamauchi told HuffPost she was sitting on the plane with her son after a five-hour layover in Houston when a man came to their row and showed his ticket, which had the same seat number as her son’s. He said he was a standby passenger.

Yamauchi said she told a flight attendant about the issue after the man arrived, but was offered no help.

“She shrugged, said the flight was full,” Yamauchi told HuffPost. “The whole transaction was very quick.”

Shirley Yamauchi The photo on the left shows Yamauchi's son sitting in his paid seat shortly before boarding. The photo on the right shows Yamauchi holding her son in her lap while a new passenger sits in his previous seat.

After the flight attendant walked away, Yamauchi, who is 5 feet 2 inches tall, said she had to move her 25-pound son onto her lap and endure the seating arrangement for the 3 1/2 hour flight to Boston. The passenger who took her son’s seat was one of the last people to board the plane, and the flight departed soon after.

The seating arrangement was so painful, Yamauchi said, that her 2-year-old had to stand or crouch on the floor at times because he became too heavy to hold.

Taizo is “half my height,” Yamauchi told Hawaii News Now. “I was very uncomfortable. My hand, my left arm was smashed up against the wall. I lost feeling in my legs and left arm.”

Courtesy of Shirley Yamauchi Yamauchi says her son was forced to crouch and stand on the floor after he became too heavy for her to hold.

No other flight attendants asked Yamauchi about the seating arrangement for the remainder of the flight, despite the fact that it violated United’s own “traveling with children” policy. The FAA also strongly advises against allowing children to sit on an adult’s lap during flights because “arms aren’t capable of holding your child securely, especially during unexpected turbulence.”

When asked why she didn’t push the issue with flight staff, Yamauchi said she was afraid of retaliation due to previous incidents on United flights that resulted in violence.

“I started remembering all those incidents with United on the news. The violence. Teeth getting knocked out,” she told Hawaii News Now. “I’m Asian. I’m scared and I felt uncomfortable. I didn’t want those things to happen to me.”

In April, a video showed airport security personnel violently dragging Dr. David Dao from his seat on a United flight after staff asked passengers to volunteer their seats for United employees who had to get to a shift on time. Dao, who was selected at random after no one volunteered, reportedly broke his nose, had his two front teeth knocked out and suffered a concussion during the confrontation.

“Those are things that happen to other people. They don’t happen to you,” Yamauchi told NBC News. “I had hoped United had changed their policy after the Dr. Dao incident.”

Yamauchi told HuffPost she attempted to file a formal complaint with United after the flight, but a customer service representative told her to call back on July 6. United did not respond to HuffPost’s emails asking about the delay.

Five days after Yamauchi arrived in Boston, news outlets in Hawaii reported on her ordeal. United then issued a formal apology to the mother.

United Airlines spokesman Jonathan Guerin said in a statement to NBC that employees had “inaccurately scanned” Taizo’s boarding pass, which made him appear to not be checked in for the flight. As a result, his seat was released to another customer, forcing Yamauchi to hold her son instead.