The film is in the Guinness Book of World Records for the costliest aerial stunt ever performed. Stuntman Simon Crane was paid $1 million to cross once between two planes at fifteen thousand feet, without the aid of any safety devices or trick photography. The insurance company refused to insure a stuntman for this, so Sylvester Stallone offered to reduce his own fee for the movie by the amount that the stunt cost to produce, in order that the film could be made. The stunt was filmed in the United States, as such a stunt is illegal in Europe, where most of the film was shot. Crane couldn't actually get inside the second plane, but good editing gives the appearance that he does.
Sneak-preview audiences saw a scene where a rabbit gets killed by gunfire. Their reaction was strong enough for Sylvester Stallone to invest $100,000 of his own money to have the scene re-shot so that the rabbit escaped.
TriStar Pictures and Carolco Pictures planned a sequel in 1994, called "The Dam", which was described as "Die Hard in a dam", and would have Sylvester Stallone's character from this movie fighting terrorists, who took over Hoover Dam, but it never went beyond the developmental stage. Stallone tried to resurrect the project again in 2008, but it never happened.
To demonstrate his faith in the safety equipment, director Renny Harlin put on a harness and flung himself out on a cable over a cliff.
Sylvester Stallone partly took on this project in an effort to help him conquer his fear of heights. He stated that he managed because he was able to inhabit a character who did not have such fears.
Renny Harlin: [Finland] The parachute that the base-jumper opens, on his escape from the villains, features the design of the Finnish flag, Renny Harlin's native country (he features the Finnish flag in most of his movies).