The wedding ceremony was almost over when newlywed Bobby Underwood stepped on a napkin-covered glass to break it, as is Jewish tradition, and everyone shouted “Mazel Tov!”.

But as he and his new wife Siobhan turned to walk back down the aisle, their wedding officiants said, “Wait.” There was a surprise.

“All of these drones started rising up,” recalls Mrs Underwood. “It was honestly remarkable, very overwhelming – and incredibly emotional for us.”

Around 300 drones appeared in the night sky, displaying lights of various colours, and forming images chosen to represent the bride and groom.

These included a baseball player hitting a ball – as Mr Underwood is a big baseball fan – and a diamond ring being placed on a finger.

The couple were married on New Year’s Eve 2024, in New York State. Mrs Underwood’s mother had arranged the surprise drone show with help from the couple’s wedding planner – who had suggested it as a “wow factor” component of the day. It seemed to have the desired effect.

“It was kind of just shock – ‘Is this really happening right now?’,” says Mrs Underwood. “I can’t believe my mom did this for us.”

Drone shows are becoming ever more popular. Once rarities, they are now appearing at occasions ranging from birthday parties and weddings, to major sporting events. Some theme parks even have resident drone shows that take place multiple nights in a row.

Glastonbury music festival had its first drone show in 2024, flown by UK-based drone show company, Celestial.

And record-breaking displays are pushing the technology to its limits – the biggest drone show in history took place in China last October. It featured a total of 10,200 drones and broke a record set only the previous month. So, does all this spell the end for fireworks?

“They are really beautiful – they are art,” says Sally French, a US-based drone industry commentator known as The Drone Girl. She says that drone shows have appeared at baseball games, corporate conferences, and even at ports, to celebrate the launch of cruises.

Drone displays are becoming highly sophisticated, she explains, with some drone shows featuring thousands of flying devices, allowing them to animate figures or patterns in incredible detail.

“I saw a Star Wars-themed drone show where there was a full-on lightsabre battle,” adds Ms French.

One barrier might be the price tag, however, with the cost per drone at around $300 (£220) in the UK, says Ms French, citing industry data from drone show software firm SPH Engineering: “A 500 drone show would be over $150,000.”

Mrs Underwood does not have an exact figure, but estimates that her wedding drone show cost tens of thousands of dollars.

The sky’s the limit, actually. Skymagic, one of the world’s largest drone show companies, has put on major displays that cost north of $1m says Patrick O’Mahony, co-founder and creative director.

Skymagic’s shows have taken place in various countries – including the 2023 Coachella music festival in California.

The company has also performed drone shows in the UK, including as part of the King’s Coronation concert, which was broadcast by the BBC.

Mr O’Mahony has worked with designers of fireworks displays and other, similar events. But drones have revolutionised outdoor public displays, he says.

His company has a fleet of 6,000 custom-designed drones. Each one can reach speeds of up to 10 meters per second. The drones sport LED lights and have batteries that allow for 25 minutes of flight time.

To make them easier to transport, the drones are stored in flight cases and unpacked at venues in a giant marquee before they are laid out in the take-off area, half a metre apart, in a grid pattern.

“Once the drones have received their ‘go’ command [they] fly the entire show,” adds Mr O’Mahony, explaining that a single human pilot on the ground controls thousands of the devices at once.

The drones are geo-fenced, based on Global Positioning System (GPS) data, which prevents them from straying beyond the allotted flight area. In windy conditions, though, they can get blown off course. In such cases, they automatically return to a landing spot on the ground, says Mr O’Mahony.

Fireworks have a “boom” factor that drones generally don’t, notes Ms French. However, Bill Ray, an analyst at market research firm Gartner, says that some drones can now launch pyrotechnics, for a firework-like effect. For instance, a stream of sparks raining down from the lower portion of an image created by a group of drones.

Plus, Mr Ray says it is much easier to accurately synchronise drone movements with music during a show, which could be another reason behind their appeal. But the cost of shows remains prohibitive to some, and in part comes down to the fact that laying out the devices and gathering them all up again after the performance is still a relatively slow, manual process, adds Mr Ray.

Pedro Rosário is chief executive of Drone Show Animations, a company that designs drone show performances for other companies that supply the drones themselves. Mr Rosário says that one challenging aspect of his work is in coming up with displays that adhere to various regulations applying to drone flights, since these rules differ from country to country. England has stricter regulations than countries in the Middle East, for example, he says.

Mr Rosário adds that drone shows, which might be paired with pyrotechnics, traditional fireworks or even lasers, allow for a huge degree of creative freedom: “You can really build something that has emotional value, it can tell a story.”

In Mrs Underwood’s case, that seems to have worked. Her guests enjoyed the spectacle too, she adds: “We’ve heard compliments about our wedding in general – but, consistently, the drone show is something people bring up as something they never expected to see.”