Kellisa Kain of Roseville celebrated a big birthday and another milestone in the skies.

Kellisa was born 15 weeks early with her twin Kirstin who didn't make it. At birth, Kellisa weighed two pounds and one ounce with all the odds against her.

"She literally had zero chance to survive and that's what the doctors told us," said Chris Kain, father. "She fought and survived."

Today, she lives with cerebral palsy and epilepsy.

Every year after was a gift, and Chris wanted to embrace all of it by showing Kellisa nature's beauty by setting a goal to hike a trail in every state.

"The idea started when Kellisa was just born in the NICU," Chris said. "She wasn't expected to survive and once she lived for a few days I kind of made a promise to her if she survived I'd do everything I can to give her a normal life."

It took them a few years traveling coast to coast, but they finally finished right before Kellisa's 18th birthday.

Her father decided to celebrate it in a big way.

He worked out with Southwest to spend an entire day flying around the country.

"I was thinking what can we do?" Chris said. "She doesn't like material things and she likes experiences."

Kellisa's sister Egypt was also along for the ride too.

"We would ask her 'Do you want a little brother or sister?' and she would sign language yes," Chris said. "We looked the adoption route and it took us a couple of years, but we got Egypt and they've been sisters since day one."

After this big milestone the family already has another goal to hike in all of the counties in California. They're planning on finishing that in a few years.