Help Needed With This Australian Cover.

I'm asking for help regarding the printed cover below used for the First Flight Australia to New Guinea by Commander Charles Ulm in the Avro Ten "Faith in Australia" on the 24th of July 1934. There are a number of different covers that can be found for this flight, and I assumed that this one was a privately printed cover, which for ages was the only one that I had seen, however I have since acquired two more similar covers.
Covers for this flight are known to have been printed by Aero Clubs, advertisers like Castrol Oil, and even personalized/hand-addressed variants some by Ulm himself, sometimes numbered with limited runs to increase their philatelic value.

The three covers I now have were all accepted at the Perth WA Post Office between the 20th of June and the 6th of July 1934 and sent to Melbourne Victoria for the flight departure. As can be seen they show an aircraft that does not even resemble the Avro Ten, as used by Ulm for the flight, so I'm inclined to think that they were not printed by an aero club, who surely would not make that mistake.
So, I'm hoping that a reader has one of these covers and maybe knows its provenance and could let me know. Any help would be greatly appreciated.

Wow, nice first official flight cover! I love it

This is the text from 'The Australian Airmail Catalogue', 6th ed 1997 pp 71-2.

"1934 (24 July) - C.T.P. Ulm, with R.N. Boulton and G.U. Allan, left Melbourne with a large mail for Papua, New Guinea and intermediaries en route. Leaving Sydney (24th), Brisbane (24th), Rockhampton (25th), Townsville (25th) and Cairns (25th), Port Moresby was reached on the 26th but due to storms, the 'Faith in Australia' did not reach Lae until the next day, 27th. All mail was back-stamped and a special cachet in violet was applied to all mail addressed outside the Commonwealth. Some covers were impressed with the cachet for transmission only between intermediaries. The return flight left Lae on the 30th, and reached Cairns the same day, Townsville, Rockhampton and Brisbane (31st), Sydney and Melbourne (1 August). Cachets were provided for mails from Papua and New Guinea. Special envelopes were printed in Australia. Facilities were provided for addressing covers to senders via nominated towns, and were thus flown both ways. Port Moresby was not called at on the return flight but the mail for Australia was taken aboard on the outward flight. Numbers flown were not officially announced but it is understood the total of outward mail plus the return mail was approximately 30,000. Souvenir cards flown on #348 (this a previous flight from New Zealand to Australia ed.) were overprinted for this flight and flown to and from all intermediaries."

64idgaf thank you for your reply and the extract from The Australian Airmail Catalogue which rightly states that "special envelopes were printed " for the flight, as can be seen below, all of which are well known and are plentiful, I show also a non-special private envelope.
Privately printed covers, some quite amateurish, were allowed and included in the approximately 30,000 covers flown, of which apparently only approx. 900 were registered.
However, my enquiry is regarding the cover in my original post, which appears to be well designed and printed, albeit having obvious error. I would love to see more and find out its history.