Maria Larios, 80, was supposed to meet her family at the Raleigh-Durham International Airport in North Carolina.
Instead, the partially blind woman from El Salvador who cannot speak English ended up in Denver after landing in Houston and being given the wrong boarding pass.
"She cannot read or write even in her own language. She can't speak English at all. So when you hand her a boarding pass, she's trusting that it's the right boarding pass," said her daughter-in-law, Mikki Paradis, according to WRAL-TV.
Larios was flying to North Carolina last week to be with her daughter, who is undergoing brain surgery.
United Airlines apologized for the mistake, refunded the woman's fare and issued her a travel voucher.
But Paradis said she did not like the airlines' response when she informed them that her mother-in-law had been flown to the wrong airport.
"They were like, 'Oh yeah. We made a mistake, and she was given the wrong boarding pass and so she's in Denver. But it's not a big deal. We've already got her on a flight to Raleigh, and we gave her a meal voucher,’" Paradis said.
United issued a statement, saying they were sorry about what happened.
"Our customer care team is in contact with her family to ensure we make this right. We are also investigating this incident internally to better understand what happened so that we can prevent this from happening again," the airlines said.
That didn't appease Paradis.
"You lost a person, and the whole time they were treating me like they lost my luggage,” she said.