As Butlin and Schedvin note the difference in the balance between US Lend Lease and Australian Reverse Lend Lease varies according to source and is ultimately a matter of judgement. At the start of the article Lend Lease to Australia is given as $2,000,000,000 but around reference 82 the article puts the difference between the two flows of aid as $100,000,000, so either reverse aid was much more that the official history states or the book value of the assets in question had been written down, from somewhere between $350,000,000 and $1,000,000,000 but how that happened is not given. Also how did $2 billion of total Lend Lease aid become $2 billion of modern aircraft in the paragraph before conclusions?
So the US makes an initial offer of $100,000,000, privately thought they could settle for $15,000,000 finally settled for $20,000,000+$7,000,000 and the Australians are not entitled to note how they ended up with a big discount from the initial offer? Also is that 78 million pounds or dollars? There is a big difference between the two. On 7 May 1946 the Australian Prime Minister reached Washington, to see the US offer dropped to $33,000,000, counter offer $20,000,000, difference split on 9 May to reach the final settlement. The consequences to Australia's air defences was nil, if later payments were made to the US for the aircraft then the settlement figure is misleading.
Lend Lease ended up too broad, for example the British asked in 1944 I think for some items to be removed so they could restart some of their export industries and being so big a sudden stop was going to cause problems.
The article has in March 1946 the US says it is abandoning the Lend Lease aircraft in Australia, do with them what you want, in May they assert title and the RAAF has to await permission to dispose of the aircraft and hand over any proceeds? It that correct? If the US did retain title to the aircraft then there should be a record of payment to the US as the aircraft were sold, I have never tried to find this so have no idea. If the US did retain ownership then they missed a chance to reclaim 2 squadrons worth of P-51 in Japan in October 1948 when the RAAF force was reduced to 1 squadron and shipped the surplus aircraft to Australia. At a time when the local USAAF was still using the type.
The main problem I have with the article is the conclusion the ultimate price paid by Australia represented a bad deal, that is not supported by the information provided. The RAAF might have wanted to keep a lot of US types in service post war but the government did not want that big an air force, and needed to make room for local production, 80 Mustang and 8 Lincoln by end 1946, plus continued Mosquito output. The British contribution to the RAAF aircraft pool goes like this, almost all trainers were RAF property, hence why they retained RAF serials, as far as I am aware the Australians paid for the Beaufighters and Mosquitoes but not the Spitfires, at the end of the war the British wrote off the aircraft in Australia, leaving it to the RAAF to dispose of them, sound familiar? So when it comes to fighters the post war RAAF had the Spitfires available. Essentially the RAAF was going to be local P-51, local Mosquito, local Lincoln with mostly local trainers, Wirraways and Tiger Moths, but US C-47 transports and Catalinas. It would require US P-51 and B-24 in service for a while to get there. Regardless of how good they were the small numbers of various US and other types on strength, like C-60, were not viable in the post war air force given maintenance requirements. When it came to local civil use the C-47 was much desired but there were lots more British types, Ansons etc. and better spare parts supply, the RAAF did not need nearly 900 of them, plus 300 Oxfords.
Australian Archives Series A11252, the RAAF Chiefs of Staff reports, weekly during WWII, monthly afterwards, around 15,500 pages of what the RAAF was up to. The RAAF makes a nice study, big enough to have a wide force mix, but much smaller than the RAF and USAAF. And the A11252 files are readable online and downloadable. They contain the inventory reports.
Next complication Lend Lease provided spare parts as well as whole aircraft, for example spares for the Hudsons the RAAF ordered and paid for in dollars in 1939/40, by 1945 there would be a lot of Lend Lease in the survivors. As the article points out trainers like Tiger Months had a higher post war market price than fighter aircraft, the former could be flown by civilians, the latter were for scrap merchants. Transports were in high demand, and the fuselages of the larger bomber types made good sheds etc. When it comes to residual price not all Lend Lease aircraft were sent new, the 12 RAAF Martin Mariners had between 229.2 and 1,385 airframe hours in prior US service, the engines between 23.6 and 890.8 hours on them.
The article states assurances were given about not expecting repayments, the reference for that actually states the debts cannot be repaid in US dollars, at least in 1945.
Airlines, Qantas, Australian National Airways, Trans Australia (Postwar), MacRobertson-Miller and so on. The Wiki article on TAA notes 16 airlines pre war. Now you can argue few of them were national, operating in all states, but they existed. Perth Western Australia had 216,000 people and its isolation made it an expensive flight, the RAAF tended to do multi stage hops when moving aircraft there, Hobart Tasmania, 61,000 Darwin, Northern Territory had 1,000 people, not a lot of customers, then post war, even with a bigger population, there was a legislated 2 national airlines policy for quite a while. Australia was one of the world leaders in aviation use in the 1930's, using national airlines as a measure does not reflect that. See also
List of defunct airlines of Australia - Wikipedia
Why did Australia's decision to build heavy bombers cause such a strain on US relations, the more Australia built the less the US had to build or finance? The associated reference newspaper article states Australia tried to license build the C-47, trying to track this down in the Australian Archives and RAAF documents comes up blank so far, while there are files on the planned post war Avro Tudor program that was ultimately cancelled. Also Australia's engine production was inadequate for the Beaufort and Boomerang it built, so any C-47 would require imported engines or fewer Australian built combat types. All up 870 Twin wasp built, 1,650 required for the Beauforts and Boomerangs, plus spares. The need for transports saw De Havilland build 87 DH.84 October 1942 to June 1943. Australian built 1,300 Gypsy Major Engines for its DH.84 (184 engines) and 1,070 Tiger Moths but exported Tiger Moth airframes only to South Africa. Minor issue, the Lancaster III used US built Merlin engines, the Lancaster I British built Merlins. MacArthur certainly wanted more aircraft repair facilities but he was not the US government.
On 31 August 1944 RAAF holdings of US types were 403 P-40 Kittyhawk, 39 B-24, 276 Vengeance, 10 A-26 Shrike, 33 B-24, 23 A-20 Boston, 72 Ventura, 71 Catalina, 15 Kingfisher, 1 P-38, 10 C-60, 55 C-47, 4 DC-2, 57 Hudson, 12 Mariner, 13 C-61 Norseman, 25 Ryan, plus another 13 C-47 and 5 C-60 on loan from either the Dutch or Americans. Ignoring the loans that is 1,048 aircraft, and the RAAF handed back 466 which were surplus? When? What types? The Hudsons were not Lend Lease, the Kingfisher and Ryans a Dutch order, the DC-2 cash purchases, a number of the Vengeances were British cash purchases, while some of the P-40 were British and Dutch Lend Lease orders transferred. In the final quarter of 1943 the RAAF handed back to the US forces the small numbers of P-39 Airacobra, Brewster Buffalo and P-43 Lancer it had picked up in 1942. While 20 P-40 were transferred in late 1944 to partially repay a "loan" from 1942.
On 28 July 1944 the Chiefs of Staff report total orders for US types were 800 P-40, 178 B-24, 135 Catalina, 67 C-47 and 15 Mariner, they do not mention the P-51 order for 285 from the US until 29 December, though it was approved earlier than that. As of 27 July 1945 the total P-51 order was for 499 as 1 had crashed in the US, along with 60 B-25, 393 B-24, 197 Catalina and 144 C-47. That is not a cut back of Lend Lease aircraft.
Australian Archives A1695 18/205/EQ which covers some of the 1945 Lend Lease Aircraft is readable online.
There is at least 3 Archive copies on the RAF Post war strength Plan D, AWM123 485, A5954 1842/3, AA196 395 but not readable online. The RAAF planned to reduce its strength to around 35,000 personnel by June 1946, and have 59 B-24, 117 P-51, 53 C-47, 21 Catalina and 16 B-25 on strength, including reserves, to help equip 34 squadrons, in January 1946 the government instruction was 20,000 personnel at most, in May, 15,000, by end June actual strength was around 24,500, end of year 13,200. As of April 1947 the personnel section was reporting authorised establishment as 15,000 including non exempted civilians.
As for the US aviation industry being the biggest US employer where does that come from, the CAA notes employment in the airframe plants, the engine plants, the propeller plants, the glider plants, the modification centres, the subcontractors, the government furnished equipment plants plus the "special purpose" peaked at 2,101,552 people in November 1943, still at 1,237,300 in July 1945, down to about 242,000 in December. US military production in 1945 was 46,865 military plus 2,047 civil types, military output dropped to 1,417 in 1946, civil production 1946 to 1949 halves each year, 35,001 in 1946 then 15, 617 then 7,302 and finally 3,545. Military production excludes gliders and target types.
The tone of the article is one where I struggle to find a single compliment, but see plenty of negative character assessments. It reads along the lines of the marriage was never good because the divorce was ugly. The US rightly had to extract some money for retained goods, much was still valuable but some of the originally most expensive items were now near worthless, others depreciated, others not worth the cost of the US retaking control but useful locally, plus just how much stuff arrived and was still around was not totally clear to either side. Negotiation time.
You may want to check out how Britain helped finance and arm continental powers for fights against Napoleon.