The dog-walking drones and flying cars of Marty McFly's fictional 21st century are still the stuff of sci-fi in real-life 2015 -- but savvy brands from Pepsi to Toyota have rolled out gadgets and gimmicks tapping into "Back to the Future" nostalgia.

Fans of the film on Wednesday will mark "Back to the Future" Day -- characters Doc Brown (Christopher Lloyd) and McFly (Michael J. Fox) blasted their way in the 1989 part two of the trilogy to what was then the great unknown future, October 21, 2015.

And major companies are not missing a trick in taking advantage of the occasion, which will feature screenings of "Back to the Future: Part II" and other events to commemorate the day.

Take Pepsi. On Wednesday, it will sell limited-edition "Pepsi Perfect" -- McFly's soda of choice in the blockbuster movie series.

The beverage giant has gone big promoting what it optimistically hailed as "the long-awaited creation," including an ad featuring flying cars, robots and a hoverboard -- a sort of skateboard without wheels and one of the enduring futuristic gadgets featured in the film.

"Pepsi fans asked and we heard them loud and clear," said Lou Arbetter, PepsiCo senior director of marketing.

"The 'Back to the Future' trilogy was as big a moment in pop culture history then as it is now, 30 years later.

"We are excited to be part of this moment and to bring fans something only Pepsi could deliver -- and there's no need to wait -- the future is now."

The bottled drink, complete with collectible case, will sell at $20.15. Just 6,500 Pepsi Perfect bottles were available, and only online.

Not to be outdone, Nike has also leapt -- hoverboard-like -- on the "Back to the Future" memory bandwagon, saying earlier this year it was releasing a version of the self-lacing Nike Mag shoes that were featured in the movie. Details though remain sketchy.

- 'Jaws 19'? -

Major car manufacturers are also getting in on the act.

Toyota, which makes a brief appearance in the film in the form of a retro pick-up truck, has launched a campaign linking its launch of the Mirai, a car that runs on hydrogen fuel cells, with the film's vision of cars running on fuel cells powered by garbage.

It even has a website (www.toyota.com/outatime/) with the words: "ON OCTOBER 21, 2015 THE FUTURE WILL BECOME REALITY."

Toyota has released a teaser video -- the full-length version will be released on Wednesday on the website -- of Lloyd and Fox discussing what the film got right and wrong about the future.

"While there are a lot of brands and activations that are celebrating the 'Back to the Future' milestone, Toyota stands apart for their nod to the future and the past with the auto technology depicted in the movies," Bob Gale, the film's co-creator and producer, said in a press release from the automaker.

Rival Ford, which reportedly provided some of the cars in the film, is getting in on the action with a mock video of a "flux capacitor" optional upgrade, supposedly allowing time travel.

The video concludes with the written words: "Obviously, this upgrade is not actually available. Happy Back to the Future Day!"

And luxury marque Lexus in June revealed its Lexus Hoverboard, harnessing magnetic levitation technology.

It has not so far attempted to tie the snazzy-looking device to the hoverboard in the film, despite the uncanny similarities.

Meanwhile, Universal Pictures also had a bit of fun with its "Jaws 19" mock trailer -- "Back to the Future" included a clip of a cinema showing "Jaws 19."

Inevitably, lesser-known gadget makers and innovators are also trying to make a name for themselves with some off-the-wall products.

California-based firm Hendo is creating a hoverboard which works on magnetic repulsion.

And while walking the dog by drone may seem still a little way off, that has not stopped some people apparently trying, according to videos posted online -- with decidedly mixed results.