For pure, kitschy Americana, it's tough to beat a huge, helium-filled cartoon character floating down the streets of New York City.

Who among us doesn’t enjoy gawking at a doughboy — as in Pillsbury — that, if he really was made of dough he'd make about 4 million crescent rolls? Or a single, angry eyebrow on a bird — that would be an Angry Bird — that checks in at 7 feet long?

The 91st Macy’s Thanksgiving Day Parade rolls on again this week with its usual complement of marching bands (12 of them this year), floats (26 of them), clowns (1,000-plus) and other performers. But, c’mon. We all know who the stars of the show are.

If the wind allows, Macy’s says 17 giant character balloons will make their way down the streets of Manhattan on Thursday, creating a lot of finger pointing among 3.5 million or so people lining the parade route and 50 million others watching on TV. These balloons, maybe even more than being kitsch or Americana or unbridled commercialism, are a testament to American ingenuity and engineering.

Really, who else would take months to design and build a balloon shaped like an acorn that is large enough to hold 15 million real acorns?

Here’s the lowdown on those high-flying Macy’s balloons ...

Yes, that's helium at work — and lots of it. An average of about 12,000 cubic feet of helium is pumped into each balloon the night before the parade. The helium, which is manufactured from a plant in Kansas run by Linde North America, is shipped to a Pennsylvania plant, converted into gas and trucked to NYC. According to Linde — this is the 23rd straight year the company has supplied the helium for the parade — somewhere around 300,000 cubic feet will be used in the parade, enough to fill a half-million Mylar party balloons.

How big are these things? At 67 feet, the Ronald McDonald balloon is as high as a six-story building. The Red Mighty Morphin Power Ranger is 78 feet long, which Macy's points out is as long as 13 bicycles. They can weigh 400 pounds or more.

What if one pops? Accidents happen. But each balloon is divided into sections — a hand, just a thumb, an angry eyebrow, a hat, whatever — so if a portion of the material tears, or a seam rips, the whole mess doesn’t melt, Wicked Witch of the West-like, into a pile of polyurethane in the middle of the Avenue of the Americas.

What if one breaks away? Each of the giant balloons has anywhere from 50-90 people marching underneath it, holding onto handles — they’re called “bones” — with the anchor ropes wound around them. First off, no balloon is going to break away from all those handlers. And even if every handler dropped his or her bone, each giant balloon has a couple “anchor” vehicles underneath too. A balloon escaping is not the real risk.

But what about the wind? That could make things a little dicey, eh? Oh, yeah. That can be risky. The Cat in the Hat was buffeted around by strong winds in 1997, hitting a street lamp and showering debris that injured four spectators. After that, New York City implemented a wind rule: The giant balloons can’t fly when winds are more than 23 mph or gusting more than 34 mph. Even with winds less than that, things can get tricky. The M&Ms balloon knocked over a lamppost in 2005, injuring two sisters.

So what do you do about that? Each balloon has a “pilot” who monitors wind speed at all times during the parade route, including at intersections (they can be particularly gusty and tricky). The pilots can instruct the handlers to pull the balloon lower, if the winds are better down there. If a particular balloon is getting a little unwieldy, there are provisions to take it to a side street to get it under control or deflate it. But those are worst-case scenarios. Winds haven’t grounded the balloons since 1971.

Who builds these things? Macy’s has had a dedicated crew called "Balloonatics" who have been building the balloons since 1969. The Macy’s Parade Studio began in a former Tootsie Roll factory in Hoboken, and since has move to a custom facility in Moonachie, New Jersey. (Here's a classic Woody Allen scene from "Broadway Danny Rose" that was filmed at the same warehouse ... mind the mild language.) There, a full-time staff sketches out designs, makes clay models, constructs them using thousands of yards of polyurethane, paints them and tests them in a process that can take up to a year.

Who’s new this year? Four giant balloons will debut including Olaf from Disney's "Frozen," The Grinch from Dr. Seuss, Paw Patrol and Jett from "Super Wings."

And who’s back? The line-up will feature the return of Harold the Baseball Player, a character featured in the holiday film classic, "Miracle on 34th Street." The Harold balloon has been recreated for the parade in black, white and gray to look like it did on screen, in celebration of the film's 70th anniversary. Also returning: Charlie Brown, Diary of a Wimpy Kid, Angry Birds' Red, Elf on the Shelf, Hello Kitty, SpongeBob SquarePants and oh, so many more.

Editor's note: This story has been updated since it was originally published in November 2015.

Up, up and away with a Thanksgiving Day tradition
The secrets and science behind those giant balloon characters in the Macy's parade.