A father and son team have completed a remarkable around-the-world flight in a small, single engine plane, overcoming some significant challenges along the way.

Key points: Kimberley-based GP Dave Berger and son Tom have flown 40,000km in a single-engine Cessna A185 from Colorado, home to Broome

Kimberley-based GP Dave Berger and son Tom have flown 40,000km in a single-engine Cessna A185 from Colorado, home to Broome The pair now know the best use for cheap vodka

The pair now know the best use for cheap vodka After a month of solid flying, the adventurers have a message for others: take care of this planet

Dave and Tom Berger dubbed their trip "Wrong Way to Australia" and deliberately chose the aerial route less travelled.

They began the 40,000-kilometre journey in the US State of Colorado where Dave had purchased the aeroplane of his dreams — a Cessna A185 — renowned for being a gutsy little plane that can land almost anywhere.

They headed north-east to Greenland, across Europe, Russia, Japan and South-East Asia before touching down more than a month later in far north Western Australia.

"When we started the journey, we thought it was unrealistic … we thought 'how are we going to get home to Australia?'" Dave Berger said.

"It felt like a very long way home."

Tracking down fuel for the plane proved to be one of the biggest challenges. ( Supplied: David Berger )

Dr Berger, who is a GP based in the Western Australian town of Broome, had great faith in his 19-year-old co-pilot.

"He's been flying with me since he was two," he said.

"He went solo once he turned 15 and has had his pilot's licence since 16.

"We're a problem-solving team."

The pair called their journey "Wrong Way to Australia". ( Supplied: David Berger )

'Treasure hunt'

The pair had to overcome language barriers to communicate with control towers, find aviation fuel and avoid bad weather.

"The whole trip across the world was like a treasure hunt for barrels of fuel," Dr Berger said.

"You just work on the problems day by day and you eventually find your way there.

"One of the biggest lessons is to keep your head and keep going and don't get daunted by the enormity of the task ahead."

Flying over a highway in Russia ( Supplied: David Berger )

One of the more memorable landings was at a disused military strip in Russia.

"It looked like it was completely derelict," Dr Berger said.

"There were trees growing on the runway and it was full of potholes."

At one strip, horses had to be chased off the grass before take-off, while other runways were at scenic locations beside a lake or nestled in between mountains.

The 40-thousand kilometre journey took in some spectacular scenery in Switzerland. ( Supplied: David Berger )

When vodka saved the day

Dr Berger and his son were in a tiny village in a Russian valley when the temperature dropped overnight to -8 degrees Celsius.

The aircraft was covered in ice, but they needed to leave at dawn because their visas were about to run out.

The immigration office was 800km away and closing at midday.

It was vital the pair got the paperwork sorted or face long delays.

But what could they do to get the plane in the air on time?

"I had internet and messaged a friend in America," Dr Berger said.

"He replied 'Have you got any vodka?'

"Of course! De-icing fluid is effectively alcohol."

The adventure was saved in Russia by six litres of vodka. ( Supplied: David Berger )

The pair dashed into town to the 24-hour store.

"It's 6:00am and I said 'We need six litres of your cheapest vodka'.

"This is Russia … nobody blinks an eye.

"It is a fantastic way to de-ice an aircraft. And if we hadn't been able to do that, I wouldn't be here now."

The pair made it to the visa office with 15 minutes to spare.

"Vodka really saved the day."

Dave and Tom Berger had to navigate some tricky, remote air strips during their month-long journey across the globe. ( Supplied: David Berger )

Friendships formed around the world

"The thing that struck us early on is the warmth and friendship of ordinary people around the world," Dr Berger said.

"Everybody likes a laugh, most people are really kind, they're really helpful and they want the best for you.

"And that was just so heartening.

"Absolutely everywhere, everyone was so helpful, particularly Russia, and that was so illuminating for us.

"That's the thing that's changed us both forever … realising we're all the same under the skin."

Flying over a river in Russia ( Supplied: David Berger )

Dr Berger was also struck by the extraordinary and varied scenery.

"In a day of flying a small single-engine aircraft that goes 240kph, you go from one climatic zone to another," he said.

"The weather would change, the geography would change.

"That was very, very sobering.

"Here we are … 7 billion soon to be 8 billion people on the planet and we're occupying a very small place.

"A very small piece of grit in a very large universe.

"It's a cliche to say but the world is really, really small.

"We really have to take care of it."