On the brink of 40, Gev Danielian could have gotten a Porsche; he could have gambled or had too much to drink. Instead, in June 2021, he planned a prudent celebration at his home in Los Angeles and allowed himself one mild regression. He blanketed his lawn in several hundred balloons.

Dozens and dozens of balloons in a palette of matte neutrals; several accent balloons streaked to mimic Carrara marble. At first, Mr. Danielian had been skeptical when his event planner, Edgar Hay, proposed them. “I was hesitant — I’m not a child,” he said.

But he came around. “Balloons are balloons,” Mr. Danielian said. “You can get balloons wherever, but the color combination he used?” He marveled at the effect, and so did his guests, he said. People stood up from dinner, and one after another sidled over to the installation; several dozen grown men and women, mesmerized, he recalled. These were not their children’s balloons.

Scroll through Pinterest now, and behold their omnipresence: balloon marquees and balloon chandeliers; balloon-forward photo booths and balloon-filled pools. Metallic balloons, confetti-filled balloons; balloon huppahs. The firm Orbis Research reported that the balloon market worldwide was worth $636 million in 2019, and that was before the pandemic seemed to spur an increase in interest not just in balloons themselves, but also in ever more complex designs.

The simple foil-letter balloons that Robin Thicke’s “Blurred Lines” made so ubiquitous were cute. Globular balloons with more sophisticated geodesic patterns than some residential homes are now an expectation.

Balloons were invented in 1824, when an enterprising scientist stacked two sheets of rubber, sprinkled flour between them and sealed the sides to create perhaps the most valuable ravioli of all time. They have since become a staple of children’s parties, awkward school-auditorium dances, and sporting events. But what balloons have not tended to be is aspirational — until now.

No one explanation accounts for their cultural ascendence, but the pandemic was a factor, moving more parties outside, and from elaborate hotels and event spaces into people’s homes, where balloons can be set up and broken down like Bubble Wrap. The reliance on livestreamed events helped too; lush, screen-filling décor looks better than sparser floral arrangements. And of course, because this is a social-media-fueled trend, there’s a Kardashian at the center of it all.

A few weeks before the World Health Organization declared Covid-19 a pandemic in March 2020, Khloe Kardashian hosted a shower for her pregnant friend Malika Haqq. There were pastel-colored roses, a five-tier cake, customized swizzle sticks, what appeared to be a smoke machine, and two enormous moss bears the size of kodiaks.

But when photos of the shower hit the internet, the masses fixated on the balloons: at least five balloon arches, two balloon stanchions, one balloon-studded wall and several cloudlike balloon structures suspended from the ceiling. There were pea-size balloons and balloons that could have doubled as flotation devices. Balloons in more shades of cream and caramel than CoverGirl foundations.

“We did Malika’s event and then the pandemic happened, so we don’t know what caused that impact,” said Jamie Andrade, 34, who founded the event design firm Balloon & Paper with her husband in 2011. The couple produced piñatas and other festive accouterments for almost a decade before balloon demand compelled them to focus on inflatables full-time.

The morning of the shower, the business had 5,000 followers on Instagram; 24 hours later, Ms. Andrade recalled, the number had swelled to more than 50,000. In the months that followed, requests for balloon installs poured in, the owners said, for parties and weddings and one circus-themed bat mitzvah. Since Ms. Haqq’s extravaganza, Ms. Andrade said she has built balloon set pieces for Drake, Katherine Schwarzenegger and Lizzo. Ms. Kardashian hired her for two more events. Ms. Andrade’s most involved installations can cost upward of $25,000.

In Nashville, the balloon design business Vroom Vroom Balloon decorated Amazon’s local headquarters with disco-themed inflatables to celebrate Prime Week. When Cano Health — a chain of senior care centers — opened in Miami Shores in December 2021, it celebrated the occasion with three site-specific balloon installations. Jazzmine Rivera, who started the Balloon River in New Jersey in 2019, is fielding more requests than she can accommodate, she said.

“We’ve had an uptick in weddings, corporate events, as well as sweet 16s and bridal showers,” Ms. Rivera said. “A lot more of the adult events, versus children. A lot of people are asking for just that ‘wow’ factor.”

The founders of Airigami, a design firm in Rochester, N.Y., have been building immersive, large-scale balloon sculptures for clients as far as the Emirates and Japan since 2005.

In 2017, the artist Lauren Messelian invited them to produce a “flower” wall for New York Fashion Week at Spring Studios. Hundreds of balloons were twisted and “planted” in different shapes and sizes to create a vertical garden. For a mall in Qatar, Airigami constructed a pair of heels made out of fist-size balloons. The finished shoes measured over six feet tall.

It’s not uncommon for the Airigami partners, Larry Moss, 51, and Kelly Cheatle, 45, to recruit a mathematician to calculate the precise dimensions of a proposed sculpture. Once Ms. Cheatle has the specs, she’ll use Adobe Illustrator to map out patterns and construct a model for scale. Then, an order is placed for the particular balloons a sketch requires. Qualatex and Tuftex are two of their preferred popular brands. Ms. Cheatle is partial to Anagram for foils.

Mr. Moss and Ms. Cheatle do their best to travel with their balloons. When work takes them overseas, Ms. Cheatle will pack the bare minimum in clothes and fill the rest of her checked suitcase allotment with latex. Mr. Moss has sometimes found it cheaper to hire an extra crew member to travel with additional balloons than to ship the material via international mail.

When it’s time for the installation, dust is a constant antagonist. Balloons are so static-filled that Ms. Cheatle sometimes has to lint roll them one at a time.

When one of their events is over, the fun starts. After almost two decades in business, Mr. Moss and Ms. Cheatle have perfected the art of the pop. The couple has tried a range of sharp objects — scissors, box-cutters, even a small spike-covered ball, which makes quick work of large-scale sculptures.

If an event hasn’t concluded when it’s time for Airigami to load out, the staff can enact a “quiet pop,” snipping the tops of balloons with a blade to minimize noise. Mr. Moss often invites the catering crew to join his team. It can be a good outlet for their frustration at the end of a night, he said.

But the new balloon fervor does not come without a cost. Climate activists point out that even biodegradable balloons are slow to decompose, and popular “balloon releases” are just a form of photogenic littering.

Balloons Blow — an organization that aims to educate the public about the effects balloons have on animals, people and the environment — opposes all balloons and advocates the use of streamers, flags and kites for event décor instead. (“Blow bubbles!” said Mary Vosburgh, one of its founders, in an interview. “You’ll get the same lift without the harm!”)

And while most balloon installers use air and mechanical fixtures rather than helium to keep their work in place, those who do need helium will find it’s harder than ever to find. “Helium Shortage 4.0,” declared Gasworld, the self-declared “market-leading news portal for the global industrial gas sector.” Prices have been on the rise, driven up because just a few countries, including the United States and Qatar, produce most of the world’s reserves.

Even Spencer Pratt, erstwhile villain on the MTV show “The Hills,” who made a habit of participating in preplanned paparazzi shoots with dozens of balloons, is chastened. His wife, Heidi Montag, has eliminated single-use plastic in their home, making balloons verboten. “I’d be canceled if I did that now,” Mr. Pratt said. “I need them to find a reusable replacement.” Overhearing him, Ms. Montag at least conceded the decorative charm: “Balloons are celebration.”

That sense of delight seems to be overwhelming environmental protestations for the time being. The demand for balloon installations in Houston is so great that not even increased competition has dented the sales of Kelsey Onstott, who owns That Balloon Girl. Ms. Onstott, 32, faced backlash on TikTok in October 2020 when she revealed that each of her installations costs several hundred dollars, but she said the uproar hasn’t affected her bottom line. Her clients see her garlands and balloon-laden “mosaics” at friends’ parties and then want to hire her.

“In Houston, it’s kind of like keeping-up-with-the-Joneses,” Ms. Onstott said. The fracas over her prices — a steal compared with what celebrities are spending! — hasn’t blunted interest in her own work. She’s never been busier.

Her success is a testament to an improbable transition. Balloons — once the cheap-metal core to florals’ 24-karat gold-plated shine — have become their own status marker at parties nationwide.

“From a business perspective, at some point event planners found balloons to be a great source of a supplement for the flowers,” said Mr. Hay, 35, the event planner who sold Mr. Danielian on the balloons for his bash and has organized parties for Sharon Stone and Kim Kardashian.

Clients, he said, would call and tell him, “I don’t have that budget. I don’t want to spend that much.’” Mr. Hay would ask himself, “How can I fill the space in order for me to make it look good and luxurious or excessive or grand, but at the same time not spend $50,000 on the flowers?”

Balloons were an answer. For small-budget events, he used them to compensate. But this was back when balloons came in standard colors and were associated more with pizza parties in movie theaters than poker nights at Charlize Theron’s house.

“It’s turned into something else,” he said. “It’s not the regular balloons that we knew — 20 in a bag. No. These are balloons that are customized for that date, colors that are customized.” When he looked back at old invoices, he found receipts for installations that cost his clients between $25,000 and $35,000.

In “The Book of Circles,” the lecturer and author Manuel Lima — who specializes in visual culture — traces a centuries-old human obsession with waves, curves, rounds and spheres: The cross-section of tree trunks, fat water droplets, infant cheeks the size of golf balls. In his research, Mr. Lima cites studies that showed babies exhibited clear preferences for undulating lines, compared with straight ones. He also writes about research that found that when asked to draw negative emotions, people tend to draw sharp, rigid lines; others, like happiness, elicit curves.

Of course, Winnie the Pooh once provided a simpler explanation: Nobody can be uncheered with a balloon.

The events of the rich and famous have their hallmarks — rooms straining under the weight of pillar candles and 12-piece bands. Flower budgets that top $100,000. Those designs elicit awe, sometimes amazement, Mr. Hay said. But joy? A lifted spirit? He’s not so sure.

“You might impress the person,” he said. “But at the same time, I notice that the person doesn’t smile.” When someone sees a balloon installation, “even if it’s small — even if it’s not $30,000, but it’s just $2,000 — it still makes them smile, because what does it do?” he prompted. “It reminds them of their childhood.”