Around midnight, guests in adjacent rooms complained about the noise and police were called.
Dumble was sleeping at the time but was woken by police and hotel staff and told to go to her own room.
According to police, she gave a staff member "the finger" and became arrogant and "lippy" as she stumbled to bed.
It was submitted that Dumble may have suffered from "sleep inertia", in which a person woken suddenly may experience disorientation and confusion about where they are and what they are doing.
Mr Dumbleton concluded that her conduct could reasonably be explained by her being "worse for drink and by her waking suddenly in an unfamiliar place to find she had to leave it".
He did not consider that the damage to Airways, or the impact on its employment relationship with Dumble was serious enough to justify her dismissal.
At most, some form of disciplinary action short of dismissal could have been justified.
He said the incident occurred at a private place, away from work before a very limited number of spectators.
He found no basis on which Airways could have reasonably determined that Dumble would have been unfit for work at 10am the next day due to the amount of alcohol she had consumed.
She was not awarded remuneration due to her contribution to the situation.
The ERA was also told Dumble's husband, Ray Dumble, took it upon himself to ring an Airways employee and abuse him in "strong terms'' about the disciplinary action being taken against his wife.
Mr Dumbleton ordered her reinstatement be suspended for 14 days while her husband's behaviour towards the employee was addressed.
In a statement, Airways maintained that its decision to dismiss Dumble had been appropriate.
"Airways is clear that the decision to terminate was appropriate in the circumstances but accepts that the authority had a different view.
"In relation to this case, the Employment Relations Authority found that Airways' process was fair and reasonable. As a safety-focused organisation, Airways is unequivocal in setting the highest standard of behaviour for all employees.''.