The Enhanced Air Cooperation initiative focused this year on fifth-generation fighter integration, aero-medical evacuation and aircraft maintenance.

Thousands of U.S. Marines on an Australian Army base this summer might be the most visible example of America’s growing military presence Down Under. But the nations’ air forces are growing equally close under a lesser-known program known as Enhanced Air Cooperation, or EAC.

The initiative, which kicked off in 2017, focused this year on fifth-generation fighter integration, aero-medical evacuation and aircraft maintenance. It involved U.S. F-22 Raptor, F-35B Lightning II, F-16 Fighting Falcon and F-15 Eagle fighters, B-52 strategic bombers and C-130J Super Hercules transports.

The Air Force’s activities in the Northern Territory, along with those of the Marines, are being supported with $2 billion worth of new military infrastructure funded by the U.S. and Australia, according to the Australian Defence Force.

At RAAF Darwin, for example, $88.65 million worth of projects have been awarded to build fuel tanks, expand the airfield and erect maintenance facilities.

These and other projects at RAAF Darwin are scheduled to be accomplished by 2023

“The major motivator for U.S. force restructure and redeployment on the western Pacific rim is China. It’s as simple as that”

The U.S. Marines with 3rd Battalion, 12th Marine Regiment, a part of Marine Rotational Force-Darwin (MRF-D), fired Guided Multiple Launch Rocket System munitions, known as GMLRS, during Southern Reach, at Bradshaw Field Training Area, Northern Territory, Australia on August 15, 2019.

The HIMARS Marines fired two GMLRS in Australia for the first time ever, according to Cpl. Kallahan Morris. The HIMARS is a weapons system made up of the M142, five-ton chassis vehicle and can carry either a launcher pod of six rockets or one MGM-140 Army Tactical Missile System (ATACMS).

The live-fire training conducted was over an area of 3,282 square miles.

HIMARS is participating in MRF-D for the first time. These Marines and equipment provide MRF-D an extended range precision strike capability that can further shape the battlespace.

the HIMARS Marines with MRF-D conducted multiple fire missions, shot two GMLRS rounds, and enjoyed training in the heat of Australia’s Northern Territory dry-season.

America has allocated more than quarter of a billion dollars for Osprey aircraft infrastructure in Northern Australia.

The US Defence Department is looking to spend $305.9 million on facilities for their Osprey fleet, Chief Minister Michael Gunner told NT Parliament on Wednesday, while knocking back a suggestion that the money would be spent on a new naval base in Darwin.

"The budget appropriation that is being sought in America is for ramps for the Ospreys in the Northern Territory, not for a naval installation," Mr Gunner said.

"The Ospreys are aircraft vehicles. That is where the money is intended to go."

In July, the ABC revealed that a draft US Congressional bill had $US211.5 million allocated for new "Navy Military Construction" in Darwin, with few other details available.

Mr Gunner said that following these reports, he had reached out to US Secretary of Navy Richard Spencer, to clarify the nature of the spending.

The ABC understands plans for a new commercial port facility were still being discussed.

A draft defence bill tabled in the US Senate last month outlines that more than $300 million has been allocated for naval construction in Darwin, the ABC has reported.

The Australian Defence Department reportedly told the ABC that the proposed funding still has to be approved by Congress, but insists that any military projects are negotiated and agreed to by both governments.

Last month Defence and NT Chief Minister Michael Gunner rejected claims a top secret naval port is in the works at Glyde Point, north of Darwin, which could eventually help US Marines operate more readily in the Indo-Pacific.

The United States military is preparing to spend more than a quarter of a billion dollars on naval construction in the Northern Territory, in a move that could raise tensions with China.

the Defence Department says it is still too early to comment on what the US military may have planned in the Northern Territory.

"The referenced document is the Senate version of the National Defense Authorization Act, which authorises (but does not appropriate) Defence initiatives," the Department said in a statement.

"It is still progressing through the US Congress and must be reconciled with the House version before it is finalised. It is not yet approved.

"We expect the US Department of Defense will provide details of the funding in accordance with its processes and timelines following consideration and approval within the United States Government."

The draft US legislation also outlines several other proposed spending projects in the Northern Territory including $US50 million for a "new airport parking apron for the Navy", and $US70.6 million for the Air Force at Tindall.