The Carvair was a relatively cheap conversion of the DC-4 / C-54 series of World War II transport by Aviation Traders (Engineering) Ltd at Southend, Essex, for an aircraft to carry 23 passengers and five cars from the United Kingdom to various parts of the European continent.

The MRTT was selected by the Australian Government for the RAAF ahead of the rival KC-767 to fulfil Project Air 5402 in April 2004 after a Request for Tender was released in June 2003 for both acquisition and Through Life Support contracts.