For the second time in less than a month, America West Airlines employees have placed young children traveling alone on the wrong connecting flight.

Krista Spears, 11, and her 8-year-old sister, Sierra, were on their way home to Lakeside, Calif., on Saturday after visiting their father in Texas. They were supposed to take a connecting flight from Phoenix to Lindbergh Field, but instead ended up at Ontario International Airport, about 100 miles northwest of San Diego.

"They put us on the wrong plane," Krista told The San Diego Union-Tribune, adding that she cried but her little sister didn't. "They sent us to another airport. I have no idea where."

"I'm sick to my stomach," their mother, Michelle Spears, said Saturday evening as she waited for the airline to drive her daughters to San Diego. "I know mistakes happen, but not with my kids."

The girls arrived about 10 p.m., nearly five hours after the flight they were supposed to take had been scheduled to land.

"We're very sorry for this mishap, and we'll do whatever to make it right," America West spokeswoman Patty Nowack said.

Spears suggested a remedy: "I told them I expect plane tickets forever."

On July 14, an 11-year-old girl flying by herself from Los Angeles to Detroit crisscrossed the country for 18 hours. At her layover in Phoenix, Aunnalise Woods was accidentally put on an America West flight to Orlando, Fla.

A week later, a 10-year-old San Diego boy flying home from Columbus, Ohio, was put on a later flight after his original flight was canceled, but the airline failed to inform his father of the more than five-hour delay.

On Friday, Tempe, Ariz.-based America West announced that after Sept. 10, it will not fly unaccompanied young children on any flights except nonstops.