The beloved pet was preparing to board a flight to the UK when he evaded animal transport staff and ran away at Tullamarine Airport.

Owner Jason Whatnall was on his way to start a new job in Wales and handed his pooch to the pet transport company AeroPets.

“I got a phone call saying that Milo had escaped and taken off and was now missing somewhere in the Tullamarine industrial estate about 5 km from Melbourne Airport,” he told The Herald Sun.

“My partner and I turned around and searched around Tullamarine, but we couldn’t find Milo.”

Whatnall added that the explanation given to him about what happened when Milo escaped was “vague.”

“It’s not clear exactly what happened. But it was done in an open area without closed gates. I think there weren’t real processes in place,” he said.

“I’m hoping the company will come up with another plan, but honestly, it’s been very frustrating.”

An AeroPets spokesman told The Herald Sun that Milo had bitten the staff member who was transferring the pet from the travel container to the warehouse.

“We advised the owners what happened immediately who came in and helped with the search for a few hours. The owners of Milo then took a flight out of Australia before finding Milo,” he said.

The spokesperson assured that they have been searching for the dog “both day and night” since he escaped.

“We have handed out hundreds of flyers in the area to neighbourhoods and businesses to assist and put food and cameras out in the night to help and have engaged social media groups,” he said.

“We have also flown in extra staff from Brisbane to assist in the ground search.”