It is an unlikely friendship that grew out of grief and has become a source of support and activism in the aftermath of the Boeing 737 MAX Ethiopian Airlines crash one year ago.

Nadia Milleron lost her daughter Samya, 24, in the crash and Zipporah Kuria, now herself 24, lost her father Joseph Kuria Waithaka.

The two are now close friends after teaming up to campaign for improved aviation safety in the wake of the disaster on March 10 that killed 157 people.

Milleron, from Massachusetts, is the niece of famed US consumer activist Ralph Nader, while Kuria is the daughter of a British family of Kenyan origin.

"We are family now, bonded by blood and by loss," Kurai told AFP as the trio walked together on a sunny winter's day through Times Square and Central Park in New York.

"I think every time we feel a bit lost, we lose a bit of hope, we look at each other and we know we are not in it alone," Kurai said.

Emotions are high, and the three often veer between tears and smiles, comforting each other affectionately.

Milleron said they hoped that "by helping each, supporting each other and understanding each other, we could prevent other families to go through what we are going through."

Milleron and Kurai have become formidable activists, taking to the corridors of power to campaign for their common cause.

Milleron, Kurai and Stumo have chaneled their grieve and anger into activism, Milleron, Kurai and Stumo have chaneled their grieve and anger into activism, Photo: AFP / Johannes EISELE

In Cologne, Kurai pressed European aviation regulator EASA to independently inspect the MAX before clearing it for a return to service.

And in Washington they lobbied regulators and politicians, attending congressional hearings where pilots and aviation experts accused Boeing of cutting corners on safety in the rush to develop the MAX as a rival to an Airbus plane.

Nadia Milleron, her husband Michael Stumo and their son Tor were among the first families at the crash site after flying to Addis Ababa immediately from the US.

"We went through a phase where we thought that they were survivors and they weren't," Tor recalled of those horrific days.

Tor Stumo (L), Zipporah Kuria Waithaka (C) and Nadia Milleron in Central Park, New York Tor Stumo (L), Zipporah Kuria Waithaka (C) and Nadia Milleron in Central Park, New York Photo: AFP / Johannes EISELE

"Then we thought we could get her body back and then we learned that there were just remains smaller than fingers, and then we learned that we couldn't even get those remains.

"And months later, the whole feeling there was helplessness and ignorance and frustration and impotence."

Samya's grave is in Massachusetts, but her family say about one-third of her remains are left in the Ethiopia soil that the plane plunged into at high speed.

Milleron and Kurai first met in October in Ethiopia. Kuria, who was born in Kenya but emigrated aged nine with her family to Britain, helped Milleron navigate byzantine African administration.

They next met in December at congressional hearings in Washington.

And Kuria, who created a website for victims' families, was in New York to hook up again and spend a week with Milleron and her family at their home in Sheffield, Massachusetts.

"Going to Samya's home I think will be another opportunity to get to know her a bit more," Kuria said. "It will also bring me closer to my dad because she was close to him when they died."

Samya Stumo had been working for ThinkWell, an NGO backed by Bill Gates focused on health care in developing countries.

She was on her way to Kenya to meet colleagues when the plane went down. It was the second 737 MAX plane to crash within five months, partly due to faulty software -- and the model has been grounded ever since.

Waithaka, 55, a former probation officer in Hull, England, had returned to Kenya in 2015 to work with communities on agriculture techniques to boost their food supply.

Milleron, Kurai and Stumo have chaneled their grief and anger into activism, lobbying for better safety standards and to overturn US deregulatory policies that contributed to the MAX tragedies.

"I gave Samya everything that I had to give her," Milleron said.

"And so it's nice that I can connect with a young lady, who is also trying to make a good difference in the world and make her father's death not in vain."