IPEC was formed in 1976 to operate the bass strait freight service linking Essendon Airport with Launceston.
The Interstate Parcel Express Company did most of their flying to Tassie. They acquired Fleet Air Services of Tasmania in 1977
they had a DC-3 VH-EWE and they painted it in the yellow top colour scheme. In 76 they already had 3 Argosys VH-BBA, IPA, IPB.
Then the DC-9s followed VH-IPF, IPC.
I remember in 76 Essendon had quite a variety of DC-3 operators. IPEC, BBA, Set Air, Forrestair, Paradac, Masling.
BBA Brain & Brown was the oldest airline started in 1949-1979.
That as much I can throw towards your question.