[2][3] EAMS was a hugely expensive plan, and to make it financially acceptable to the British Government, subsidies were required to support it from the dominions (especially South Africa, India and Australia) and colonies of the Empire.
Australian aviation experts were deeply sceptical about the Scheme from the start, and were especially concerned that Imperial Airways had decided on the use of flying boats to operate the new services, even before final agreement was reached.
[6] In December 1938, the Scheme was in crisis, as some Shorts flying boats were out of service due to accidents, while the cheap subsidised mail rates offered to the public attracted a flood of letters that the British Air Ministry never expected.
To shift this huge quantity of mail while their own fleet steadily diminished, Imperial Airways scoured Europe for aircraft on short-term leases, including American Douglas airliners from Swissair.
[4]: 86 An official review of the Scheme in early 1939 then concluded that the amount of mail to be carried at peak times like the Christmas season could never be lifted without an uneconomic number of 'reserve' aircraft that would then be idle for the rest of the year.