Roberto Formigoni, the ex-president of the Lombardy region, can be heard in the video below yelling “d**khead" at someone down a phone at the check-in desk, before slamming the receiver down, sending papers flying.
The outburst, filmed by airport passenger Andrea Spedale and shared on Facebook, unfolded late on Tuesday night.
“I don't know exactly what happened,” Spedale wrote on the social media network, “there were flight delays, a big group came together and they all boarded. After quite a while, he arrived…only him…and he was the only one left on the ground.”
Formigoni later claimed that he was late for boarding the 10pm flight to Milan because the airline switched the flight's departure gate four times, and has pledged to seek compensation.
“I was meant to take the last flight from Rome to Milan at 10pm and arrived on time at gate B2,” he told La Stampa.
“From there, they sent me first to gate B11, then B6 and then B27, where I arrived at 9.50pm. They didn't let me board because they said I was late, but now I'm going to claim for damages.”
Alitalia was on the brink of bankruptcy before merging with Abu Dhabi's Etihad last year.
Formigoni fumed that the “Italo-Arab” merger, which “cost the taxpayer dearly" has not worked. He went on to describe the company as being full of “incompetent, incapable and dishonest” people.
He also took issue with the Facebook poster, saying that “those who comment without knowing the reality are complicit with the disruptions of the so-called national carrier towards travellers.”
But Alitalia disputed his claims over the gate changes, saying the senator had “failed to show up on time”.
“The flight left on time, so it was no possible to board late passengers.”
The company made no comment in response to Formigoni's reaction to missing the flight.