Your decision to have the snakes desperately trying to escape during the playing of the in-flight movie Monster In-Law seemed like an unnecessary dig and adds nothing to the rest of the film.
We found it hard to believe that during a layover in Cleveland no one remembered to remove the snakes from the plane.
We don't feel that a song and dance number is appropriate for this film, let alone one as confusing as what you wrote. In it, the snakes and the humans team up, including several people who, in previous scenes were bitten and either killed by the snakes or in grave condition. Even more strange, it is as if for portions, you forgot everyone is on a plane. You have them dancing on mountain tops, on ice bergs and at one point, you have them doing a tango under the sea. By the time the whole number is done, which to our estimates is 20 minutes later at the earliest, the viewer completely forgets where the plot left off.
Let' get rid of the scene where that king cobra attacks and kills a man for kicking the back of his seat. Snakes don't need reasons for killing people. They're snakes.
We found it odd when the pit viper was about to sink his teeth into the neck of a young lady, but happens to look her in the eyes and fall madly in love with her. Even stranger, the young lady does not convince the viper to help the humans, but instead, the viper convinces her to help the snakes. Just a side note here, as a rule of thumb, 90 minutes into a film is too late to start a love story, especially one involving a snake and a human and especially when the relationship ends ten minutes later because of jealousy.