Preparations for US president Barack Obama's weekend visit to Brisbane have ramped up with the arrival of the presidential car, The Beast.

Late Thursday afternoon a US Air Force C-17A Globemaster III carrying the president's security personnel and equipment landed at Amberley Air Force Base ahead of the G20 Leaders' Summit.

Among the vehicles unloaded from the military transport aircraft was the US presidential state car, known as The Beast.

Two of the armoured Cadillac-badged limousines - known as Cadillac-1 when the president is travelling inside - departed the air base near Ipswich along with a series of black four-wheel-drives, believed to be carrying US protective services officers.

The vehicles - one for the president, the other which serves as a decoy - are fitted with military grade defence systems and 20-centimetre-thick armour-plated doors.

Mr Obama's convoy has been known to stretch up to 50 vehicles and feature a counter-assault car, media vehicles and emergency services vans.

David White, a vintage aviation enthusiast and co-presenter of ABC digital radio program Canvas Wings, spent hours at Amberley to see the goings-on ahead of the summit.

"There [were] at least 30 Australian police cars with [the US cargo], so it was quite a big convoy," he said.

A US Air Force C-17A Globemaster III carrying the president's equipment arrived at Amberley. ( Supplied: David White )

While the plans for Mr Obama's arrival in Australia on Air Force One on Saturday are kept secret for security reasons, Mr White said details can be pieced together from documentaries, films and previous presidential entourages.

An Australian Army Black Hawk helicopter performs an operation west of the G20 host city. ( Supplied: David White )

"I've been looking in the skies for decades now and obviously never seen anything like this in Brisbane," he said.

"Opportunities like these are rare."

The precious presidential cargo landed after an Australian Army Black Hawk helicopter did practice manoeuvres over Amberley, including exercises which saw troops dangling from the aircraft.

The arrival of the presidential vehicles came a day after two Osprey aircraft and two VH-3D Sea King helicopters, which will transport Mr Obama during the summit, performed operations in the host city.

While much of the attention will be on the US president's entourage, Mr White said most of the world leaders have made similar arrangements, with Russian president Vladimir Putin and Chinese president Xi Jinping also expected to travel in large motorcades.

Dozens of police officers accompanied the US presidential vehicles. ( Supplied: David White )

Plane spotters have already sighted a Russian Ilyushin Il-76 – a special cargo aircraft rarely seen in Australia – and a Saudi Boeing 777.

"That's the beauty of the summit for people like me," Mr White said.

"Especially ones like the Ilyushin, the ones the Russians have got, we don't see a lot of these types of aircraft from around the world here too often."

The Brisbane summit will host 25 world leaders altogether and another 10 internationally protected delegates.

Prime Minister Tony Abbott will arrive with British prime minister David Cameron in Brisbane on Friday evening after attending the East Asia summit in Myanmar.