The Ryanair flight left Manchester Airport for Tenerife on September 18 but had to make an emergency stop in Portugal. Local police had to be called to escort passengers off the aircraft.
The pilot reportedly had no choice other than to make the emergency stop on the Portuguese island of Porto Santo.
The man who reportedly urinated on his seat had apparently been told to sit down by flight attendants many times.
A passenger onboard told The Liverpool Echo: “The flight was delayed at Manchester Airport so there was more drinking time.
“Usually when you get on a delayed flight, the first thing you hear is the captain and cabin crew welcoming you on board and apologising for the delay.
“But straight away the first announcement on the system was ‘anyone found drinking their own alcohol or smoking in the toilets will be dismissed from the plane and if needs be we’ll divert’, so they were aware of this passenger straight away.
“The guy was just wild. He was very drunk and was up and down out of his seat and was told to sit down loads of times.
“Eventually, he wanted to go to the toilet but he was told no, so he stood up and there was an empty seat adjacent to him and he just revealed himself and had a wee on the seat.”
The passenger said that people couldn’t reason with the man or even talk to him as he was “gone”.
Disruptive passengers can force planes to be diverted if cabin crew are unable to control them.
Normally local police will be contacted and escort the passengers from the plane. They could then be arrested in some cases.
Rowdy passengers could be banned from airlines or face fines for their behaviour. Serious cases could even result in criminal charges.
In May, Jet2 slapped a lifetime ban on two brothers after their aggressive behaviour forced a plane to divert.
The holiday company said that the crew had no choice but to divert the aircraft to Corfu instead of continuing to Crete.
Jet2 then had to provide accommodation, food and transport for passengers as they were unable to reach Crete as scheduled.
The airline said it had a zero tolerance approach for aggressive behaviour and banned the brothers for life.
The disruptive pair also had to pay a £50,000 fine after showing unacceptable levels of violence.