"I couldn't even believe it. And all these people are staring at me, and I just, it felt like I was in a dream. It was crazy," she remembered.
Amid the high-altitude drama of screams and cheers from fellow passengers, Hallsted said yes. Today, she goes by Amanda Walker. The couple, married nearly two years, had their wedding in Utah, on the ground. They live in New York, where Amanda Walker works at a design firm while Derek Walker pursues his graduate degree.
These days, flying together resurrects the memory of their engagement, Amanda Walker said.
"Whenever we fly in a plane now, it's kind of like reliving it," she said.
But if they ever feel like actually seeing that memory, they can with just a few clicks of a keyboard. Derek Walker's mother filmed the proposal on her camera and posted it to YouTube, where it's attracted more than 200,000 views.
The Walkers aren't alone. Type the phrase "airplane marriage proposal" into YouTube's search engine and you'll get hundreds of results.
Derek Walker said that proposing on a plane is an unconventional thing to do in an otherwise conventional situation, and that's why people like it.
It helps, Amanda Walker added, when a plane load of passengers is celebrating with you.
"The whole plane was screaming, and cheering, and they were all so into it," she said. "It makes it so much more exciting."