The comedy's co-writer told Entertainment Weekly that the scene - in which Kristen Wiig's character Annie acts outlandishly after being given pills by rival Helen (Rose Byrne) as the bridal party travels to her best friend Lillian's (Maya Rudolph) bachelorette party in Las Vegas - was a late addition.
Mumolo recalled: "When we finally wrote [the airplane scene], it really made us laugh and we saw the opportunity for what it could be and the potential that it had. It was actually one of the easier scenes for us to write. I don't know if that's because sometimes when you don't have enough time to overthink anything, you don't.
"We just had so much fun with it. This scene just took off very easily. When we finished that scene, there was a feeling of, 'Wow, I'm so happy that this change was made and happy that we ended up with that.' It was a good exercise in letting go. The movie-making process, everything changes at every step. We took something out and we were nervous, and then we ended up with something better. It was a really good learning experience for us."
"We knew where it going to end up, but getting to that point, where they're going to kiss, was a very difficult obstacle to overcome. It can't come across as a Girls Gone Wild moment. It comes out of desperation. [But] they pulled it off with flying colours."
Mumolo added that she was pleased with Bridesmaids' success in light of the fickle entertainment industry climate, adding: "We're just so happy to know that with something like this, there was a place for our voice.
"It's not easy getting a movie made. It's extremely difficult and the process was tough, so by the time the movie came out, it was almost anti-climatic because the making of the movie is the tangible experience of it. [The success of the film] was very surprising, for sure, but exciting and overwhelming."
> 'Bridesmaids' co-writer joins Judd Apatow comedy
> Kristen Wiig: 'Bridesmaids casting was important'
Watch the trailer for Bridesmaids below: