As Wilbur and Hiro are from different series, they have never met in canon. Even though a few Disney crossover video games could have the dark haired boys crossing paths with each other or get them added in the same team, by the player's choice.
Both of their Disney films have something to be with science and the people that work in that field. Hiro being one of them, while Wilbur enjoys using some of his father's inventions like the time machine. Hiro's robotic friend, Baymax, was build by his late brother, Tadashi, and had upgraded "him" so Baymax could help him take out Yokai. Both the first time machine and Baymax's 2.0 armour are red, and Hiro and Wilbur have flown through the air on/in them. Just as Hiro is very close with a robotic nurse, Wilbur is very good friends with Carl the Robots who was also build by his father. One of Hiro's (human) friends and superhero teammate, Honey Lemon is into art, just as Wilbur's cousin Laszlo is the artist of the Robinson family. Even though Hiro is the leader of a superhero teams, Wilbur does have an uncle that dresses and acts a bit like one, along with his uncle's portrait looking like an image from a comic book. Despite Wilbur being an only child while Hiro had an older brother, as well as him losing his parents at a young while Wilbur still has his, both Hiro and Wilbur live with their aunts; and their family pets.
Just as Hiro builds the gadgets to help him and his team with their work, the prologue video game of Meet the Robinsons has Wilbur using a set of devices that he uses in the game's prologue storyline. The game also has Wilbur facing a lot of bad robots, while Hiro faces similar kind of bad robots in the Big Hero 6 TV series. Wilbur's video game and Hiro's TV series also has both of them making their way into other people's labs and helping people in need of large or small help from them. Wilbur's personal, character logo icon is the lightning bolt logo on his clothes, while Hiro's is the microbot shaped H in the Big Hero 6 TV series. Since a few Disney characters, like the Disney Princesses, do have their own iconic marks that references them alone or their Disney films.
Wilbur's film is based on a novel of the same name, while Hiro's is drawn from a Marvel comic of the same name as well. Along with it being the main reason why Hiro is sometimes considered as a Marvel character.
Hirbur is part of the Modern/Futuristic Four crossover Disney fandom, where Hiro and Wilbur are two of the four main members of it along with Violet from The Incredibles and Penny from Bolt, and the only slash ship of the Modern 4. Even though there have been a few fans who have the ship rival with the other Big Hero 6/Meet the Robinsons crossover ship, Hirowis.
As it is a main pairing from a crossover fandom it is common used in AU scenarios. In some versions of Superhero AUs, Wilbur is sometimes given thunder or electric related powers to reference the lightning bolt logo on his shirt and the cap he lends Lewis. While Hiro's fan-given superpower commonly has something to be with telekinesis to reference the Nero-transmitter head band he had made to control his microbots. There have even been times where the Superhero AU has Wilbur wearing BH6 style armour that Hiro made for him. Just as Superhero AU's relate to and references Hiro and his world, Time Travel related AUs references Wilbur as they travel through time together. In time travel AU's, Hiro would ask or take Wilbur's time machine to save Tadashi, while Wilbur would do what he can to talk Hiro out of it. There have even been fans who have portrayed Wilbur and Hiro as Jay and Carlos from Descendants, while Violet and Penny are seen as Mal and Evie.
On AO3, the ship only has 6 fanfics, while fanfiction.net has 3. Even though the ship has small support on a few fanbase websites, like Tumblr and Deviantart, it still has fans.
- They are two of the playable characters in Disney crossover games, like Disney INFINITY, Disney Emoji Blitz and Disney Heroes: Battle Mode.
- Wilbur has a bad boy nature-like while Hiro has a nerdy-like one.