The airline confirmed flight EZY1963 made an unscheduled landing in the city on Sunday (August 19) after the passenger became abusive towards flight crew.
Passengers told the Gibraltar Broadcasting Corporation the man escorted from the flight was “drunk” and “rowdy”.
Two other passengers also disembarked in Porto. The aircraft eventually arrived in Gibraltar around an hour late.
An easyJet spokesperson, The Sun reports, said: "easyJet can confirm flight EZY1963 from Manchester to Gibraltar diverted to Porto on August 19 due to a passenger onboard behaving disruptively.
"The safety and welfare of our passengers and crew is easyJet’s highest priority. EasyJet’s crew are trained to assess and evaluate all incidents. While such incidents are rare, we take them very seriously. [We] do not tolerate abusive or threatening behaviour onboard and always push for prosecution.
"Police met the aircraft on landing and escorted the passenger off the aircraft. Two customers accompanying the passenger also chose to disembark.”
It comes just days after the CAA warned the number of incidents of in-flight drunken behaviour could hit record levels this year.
According to the CAA, the number of incidents reported per year by airlines has quadrupled since 2013, with 417 reported last year.
The number stood at 202 by mid-July this year, ahead of the busy summer season.
