For some on board a British Airways flight it was the first time they heard the emotional news.
Travellers from the United Kingdom told Boston News they were having a difficult time imagining a future without Queen Elizabeth II.
"It's not good, especially as I was 40,000 feet in the air," Jean Addison of Wales said.
"It just seems odd that she's not going to be there."
Video spreads message
A video has gone viral of the moment a pilot informed passengers and cabin crew of the news the Queen had died.
On a British Airways flight out of New York City on Thursday, the pilot could be heard telling those on-board over the speaker that Queen Elizabeth II had died.
He delivered the news moments before landing at Heathrow Airport.
"The Queen passed away earlier today with her family by her side," the pilot said.
"I thought at the moment I should at least tell you that before you arrive at the terminal, because I know many will be very, very sad about this.
"It will give you some time to reflect because we have 40 minutes for landing."
The pilot continued: "We will all be thinking about her family in this time."
Two flight attendants on opposite ends of the cabin are seen dabbing their eyes, while some passengers had stunned looks on their faces.
The clip was taken by Laerke Christensen, who was on-board the flight, and shared to YouTube by Storyful.
In the five hours since it was posted, it has already clocked more 74,500 views and over 400 comments from online users applauding the pilot for his "thoughtful" act.
"Wow, even on a plane. That's solidarity," one person wrote.
"I'm sorry for the people who had to hear this news on the plane … I have never cried so much on this day in my entire life," another woman added.
Palace confirms Queen's death
Buckingham Palace confirmed in a statement at 6.30pm on Thursday (local time) Her Majesty Elizabeth II, the longest-serving monarch in British history, had passed away, making her son, Charles, King.
She died "peacefully" at Balmoral Castle in Scotland after Buckingham Palace revealed she was under medical supervision amid escalating concerns for her health.
The royal family confirmed her death around 8.30pm local time (3.30am AEDT). She was 96 years old.
King Charles III – who immediately ascended the throne following his mother's death – issued a statement about the royal family's devastating loss.
"The death of my beloved mother, Her Majesty the Queen, is a moment of the greatest sadness for me and all members of my family," he said.
"We mourn profoundly the passing of a cherished sovereign and a much-loved mother. I know her loss will be deeply felt throughout the country, the realms and the Commonwealth, and by countless people around the world.
"During this period of mourning and change, my family and I will be comforted and sustained by our knowledge of the respect and deep affection in which the Queen was so widely held."
