Big Trouble

In a high-school game of "Killer" (in which a student must shoot another with a squirt gun), Matt Arnold has to "kill" classmate Jenny Herk, and decides to sneak up on her at home. By coincidence, hitmen are also there to assassinate Arthur Herk, who has secretly embezzled money from his company, Penultra Corp. When the fake assassination attempt crosses paths with the real one, police officers Monica Romero and Walter Kramitz are called out to the resulting disturbance. During the chaos of the assassination attempts, Matt's friend, Andrew, called Eliot Arnold, Matt's father. Upon arriving to pick up Matt from the Herk's, Eliot immediately feels a mutual attraction to Anne Herk, Jenny's mother, as Matt and Jenny begin to feel attracted to each other as well. The Herk's housemaid, Nina, meanwhile, falls in love with a young homeless man named Puggy, who lives in a tree on their property, after she runs from the shootings and he saves her from the hitmen.
Realizing that he is the intended victim, Arthur visits arms dealers to buy a rocket but is sold a suitcase nuclear bomb because the dealer claims to be out of rockets and doesn't tell him that it is a nuclear weapon. Escaped convicts Snake and Eddie, who were previously kicked out of the bar for disorderly conduct, hold up the bar and kidnap Arthur and Puggy (who is an employee there) and take the suitcase, not knowing its contents.
Meanwhile, Matt tries to "kill" Jenny in a mall parking lot, but a security guard thinks that Matt's gun is real and opens fire on them. Matt and Jenny run away and eventually return to the Herk house, followed by officers Monica and Walter, who stumble across the confusion. Eliot is called over once again.
The convicts force Arthur to return to his home, where they capture everyone and tie them up. Taking Puggy and kidnapping Jenny, they leave (with the suitcase) for the Airport. Nina, who was hiding in her room, frees everyone except for Monica and Arthur (who were handcuffed to an entertainment system). Shortly after, the house is visited by two FBI agents who are tracking the bomb. They free Monica and have her lead them to the airport (leaving Arthur, as he was poisoned by a hallucinogenic toad, causing him to think that his dog is possessed by Martha Stewart).
The criminals pass through security with Puggy and Jenny, where the bomb is inadvertently triggered and its 45-minute timer begins; Puggy manages to escape in the confusion of boarding the plane. The FBI agents tell everyone that unless the bomb is retrieved soon, the plane must be shot down. Puggy leads the group to the criminals' plane, which Eliot sneaks onto. Meanwhile, the two hitmen get out of the traffic jam (caused by Snake and Eddie) and reach the airport. They bump into Officer Romero, and Special Agents Greer and Seitz, knocking the hitmen's Remington sniper rifle out of their golf bag in the process. Romero grabs the rifle, removes its bolt (rendering it useless), and returns it.
Eliot, having sneaked onto the plane, attacks the criminals by knocking Eddie out with a fire extinguisher and blasting the extinguisher at Snake. On hearing the case is a bomb, Eliot hurls it out of the still open rear door, only for Snake to leap after it. In a memorable feat of dumb luck, Snake manages to cling onto the door's steps. Despite Eliot's insistence that the case is a bomb, Snake opens fire on him which prompts Eliot to pull the emergency lever which decouples the door. Snake plunges into the ocean with a defiant smile, still clinging to the bomb, which explodes safely in the water. Eliot is congratulated by the FBI, promised he will receive presidential cowboy boots and a hat, and told the events that took place are strictly top secret.
The last scene reveals what happens to the main characters: after chasing down a plane, subduing two criminals, and saving Miami from a nuclear disaster, Eliot finally won Matt's respect. Anne and Eliot get married a week after Anne gets divorced from Arthur. Walter, after a forced strip search by the airport guards, becomes a male stripper and marries. The two hitmen manage to escape Miami after a series of very weird events. They claim their Miami job was the lowest point in their careers. They were surrounded by the fans of Florida Gators on their plane home (which was a constant joke in the film). Eddie goes back to jail in a prison outside of Jacksonville, but becomes friends with another dimwitted inmate who shares the same affinity for crude jokes as Eddie does. Arthur is last seen still handcuffed and tormented by his dog.

Question: What did Eliot sneak onto?
Answer: A plane