The story
Express Freighters Australia commenced operations on 24 October 2006, initially operating one Boeing 737-300 on a wet lease from Australian airExpress. and expanded to four aircraft during 2007.
The four 737s supplanted Boeing 727-200s previously operated on behalf of Australian airExpress (itself a joint venture between Qantas Freight and Australia Post) by National Jet Systems.
From Wikipedia’s article on Express Freighters Australia, shared under CC BY-SA 4.0.3