A probable explanation for a recollection of a UFO during the historic Smith flight landing in Adelaide in March 1920

The 1947 recollections of the March 1920 Smith arrival in Adelaide   

from my report to a November 2011 Magonia Exchange & Project 1947 discussion

Keith Basterfield reported on February 1947 (not February 1946)  item back
in January 2011
http://ufos-scientificresearch.blogspot.com/2011/01/cold-case-port-augusta-5-february-1947.html
I am pleased that Ole Jonny Braenne has drawn attention to the actual date
of the return of the Smith flight back to Adelaide as Tuesday March 23rd
1920.

I have now had the opportunity to look at the Adelaide Advertiser around
that date.  The coverage of the events leading up to the Vimy landing (The
Smith plane) suggests that the 1947 recollection by H.N. Wicks of the 1920
events may be confused.  The "two large black objects" may well have been
the biplanes being flown by Captains A.R. Moore and Captain Loftus.  These
planes eventually escorted the Vimy piloted by the Smiths - the stars of the
day's spectacle - called "Our Knights of the Air" by the local paper.
Elsewhere in the papers coverage we see reference Captain Butler having a
delayed take off, finally leaving sometime after 1pm.  The planes of Moore
and Loftus appear soon after, preforming "evolutions" over the aerodrome.
The Vimy was first seen at 1.45 pm not far from Mount Lofty.  It was soon
joined by the two local planes piloted by Moore and Loftus, finally landing
soon after 2.12 pm.  As for Captain Butler's plane, it seems his flight was
a matter of some anxiety.  He turned up at 2.45 pm, saying he had been
unable to "pick up" the Vimy, described elsewhere in the coverage as "a
mammoth compared with the other machines." He put his inability to find the
Vimy down to the mist in the hills.
So I suspect that the various observations of Mr. Wicks recollected in the
1947 letter to the editor, were of Captain Butler flying over the area and
the other two objects sighted were the two other local pilots Moore and
Loftus.
Happy to hear of any other suggestions.  So far I haven't picked up on any
March 1920 accounts or letters suggesting mysterious objects flying around
that day.