|“||Spent my whole life here building the Snow Flyer 3. My wife and kids left me, but I'm here. I feel good! I did it, Dad!||”|
— Sergio McGuinness, "Love Toboggan"
Sergio McGuinness is a man who broke the land speed record on snow. He claims his father and grandfather died trying to break the record and his wife and children left him while he was working on The Snow Flyer 3.
Sergio was very proud of his accomplishment, having spent his entire life building The Snow Flyer 3 after both his father and grandfather passed away working on the same project. He pursued his dream relentlessly, to the point both his wife and children left him.
Upon having the plaque taken from him after Milo, Melissa, and Zack broke his record on a toboggan, he promptly snatched back the plaque and escaped with it in his vehicle.
Sergio has an angular face with dark brown eyes and an olive complexion. He has very short, curly brown hair, thick eyebrows, and a large mustache. He wears a red full-body racing outfit with black accents and patches on both his chest and his arm.
In "Love Toboggan", just as he had been given a commemorative plaque, Milo, Zack, and Melissa inadvertently broke his record. The camera crew filming him were going to take his plaque, but before they could Sergio jumps into his jet-propelled sleigh and flees with law enforcement hot on his tail.
In "Pace Makes Waste", he is still being pursued by the police. When he goes to reach for a hotdog that landed on The Snow Flyer 3, he crashes and the engine comes loose and flies away.
In "First Impressions", his past self was shown, showing his then alive father his newly finished The Snow Flyer 1.5. Just then, the rocket activates on its own, (likely due to Murphy's Law) and flies right off the body of the vehicle. Sergio then says that he'll get busy on The Snow Flyer 2. The rocket from the 1.5th version of The Snow Flyer crashes into Milo's school bus and makes the bus go ridiculously fast.
Sergio has dedicated his life to building the world's fastest snowmobile, an invention that he calls "The Snow Flyer". He has made numerous prototypes of these vehicles, all of which have failed with tragic results including the deaths of his family members, the divorce of his wife, and the loss of custody of his kids. All of which have hurt him deeply but none of which have stopped him from achieving his goal, which he eventually did, only to be almost immediately upstaged by Milo, Zack, and Melissa, who beat his record completely by accident. To this day, Sergio is still being chased by cops, while he drives away from them, with his undeserved award, that he refuses to give up.
- Snow Flyer 1 - The original Snow Flyer was built when he was relatively younger than he was in "First Impressions", which is somewhere around 7–8 years ago. It was mentioned in "Love Toboggan" that his grandfather died on the first Snow Flyer while testing it out.
- Snow Flyer 1.5 - In "First Impressions", Sergio finished the second Snow Flyer, which he considered to be a second version of the first one, rather than a new version altogether, giving it the title, "Snow Flyer 1.5". While showing this to his father, the rocket booster was set off, prematurely and got launched off the body of the vehicle, making his second prototype a bust. Immediately after it failed, Sergio was determined to work on The Snow Flyer 2.
- Snow Flyer 2 - Little is known about The Snow Flyer 2, other than the fact that Sergio's father was killed on it, possibly in the same way as his grandfather in the original Snow Flyer.
- Snow Flyer 3 - Sergio dedicated years of his life to building The Snow Flyer 3. He spent so much time obsessing over the machine, that his wife and kids left him, for not paying any attention to them. Sergio was torn apart by this but he continued to work on it anyway. Finally, he finished the machine and not only was it successful and safe but it also became the fasted snowmobile in the world. In "Love Toboggan", Sergio earned an award for his achievements and he was finally happy, despite all that he lost, during its creation. Just after claiming his award, Milo, Zack, and Melissa blew right past him in a rocket-propelled sled, which heavily outranked The Snow Flyer 3 in terms of speed. When this happened, Sergio lept into The Snow Flyer 3 and took off with the undeserved award, while the cops chased after him. The Snow Flyer kept moving for weeks, until the episode "Pace Makes Waste", when Murphy's Law struck again. Milo and Elliot drove past them in a pace car, which caused the rocket booster to break off of the body of the car and slam into the back of their own car.
“Ladies and gentlemen, on behalf of the team, I present this placard to Sergio McGuinness, who has broken the land speed record on snow aboard his ship, Snow Flyer 3!”
“Thank you, thank you; I cannot believe this day has happened! I've worked for this dream my entire life!”
“You'll never take me alive!”