The political and cultural aspects of the operation were probably a little remote from the pilots of the day, who would concern themselves more with the actual operation, the different weather conditions encountered, and such like. It would be the management and, behind the scenes, the sponsoring government, who would be more into these aspects
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I agree with WHBM that there may be a mis-match between your objectives and the belief that pilot biographies would be a good source. I also support all those recommending the Frater book. The social history of air travel is remarkably undocumented relative to the hardware and commercial and military aspects. I am only aware of two books, which are themselves closely connected. They are Air Travel - A Social History by Kenneth Hudson (Adams & Dart 1972) and Diamonds in the Sky by the same author & Julian Pettifer (Bodley Head 1979 ISBN 0-370-30162-5) The latter was an updated version of the former made in conjunction with a BBC TV series of the same name. Pettifer was the presenter.
Concerning the comments on the make - up of the passenger lists, I think it may be in one of these books that there is a comparison of the Far East services of Imperial and the competing Dutch KLM service to their then East Indies colony. This noted that the Imperial service was aimed primarily at Government related traffic to various British or British dominated territories on the way to India and beyond. Consequently , having many stops was not seen as a disadvantage. KLM on the other hand needed to get its passengers to their territories as fast as possible. This had the unintended consequence that business traffic from Britain to Singapore in particular always flew KLM with the result that Dutch passengers had difficulty in finding space.
For good coverage of the KLM v Imperial competition to the far east there is a another pilot biography, that of Ivan Smirnoff, Russian born KLM captain - The Smirnoff Story by Anne Robertson Coupar Jarrold 1960.