"She didn't know me, I didn't know her. She just said, here's a lasagna and good luck."
At the time, Stansel had been suffering with chronic kidney disease for more than a decade.
Stansel and Harskamp soon flew on the same Alaska crew together many times and became friends.
In March of 2016, Stansel became too sick to work. Her doctor said she would die without a kidney transplant.
Harskamp was tested immediately: perfect match.
"She had actually said, 'I am going to serve you my kidney in an ice bucket on the drink cart," Stansel recalled. "From the very beginning, she had no doubt that she was going to be my donor and I kind of felt the same way."
The transplant will happen at Swedish in Seattle on Monday. Both women are eager for Stansel to be healthy.
"I always say, I'm going to lose a kidney but she's going to live.
It's a pretty fair trade-off, and pain is temporary," the pilot told KIRO-TV.
It's "so bizarre that she would end up being my perfect match; we're just so alike in a lot of ways," Stansel said.
Harskamp must be cleared by a flight surgeon and the FAA before she can pilot a commercial jet again.
She hopes to be back at work within a month.
Stansel's recovery will take longer. She has to make sure her body is strong enough to endure what she calls "the germ-filled tube" she works in.