Border police intervened when the man, who had flown from Manchester to Brindisi in Apulia with budget carrier RyanAir, was apparently unable to wait to use the airport toilet.
The 68-year-old removed his trousers and defecated on the asphalt at Brindisi airport, between the aircraft and the gate to the airport, Italian media reported on Wednesday. He was unable to give an explanation for the act, and was described as being in a "state of mild agitation".
He received a fine for €3,333 for 'obscene acts' a few days after the incident while on holiday in Lecce, according to local paper Brindisi Report.
Police intervened in a separate incident at the southern Italian airport on Monday, after a married couple had a fight while the plane was refuelling.
The husband disembarked from the aircraft - a Thomas Cook flight from the UK to Corfu, which had been diverted to Brindisi due to bad weather - despite having been told he was not authorized to do so. He was charged with failing to comply with safety standards.