Travelling long haul in 1939: Melbourne to New York (2015)
nla.gov.au
nla.gov.au
https://en.wikipedia.org/wiki/Boeing_314_Clipper
https://en.wikipedia.org/wiki/Short_Empire
I am not certain on the exact economics of it, but have read that the inflation adjusted round trip ticket cost of flying from Los Angeles to Australia by flying boat in the late 1930s would be similar to, or slightly higher than, the very top tier of first class long haul airline travel today.
https://www.etihad.com/en/fly-etihad/our-cabins/the-residenc...
On the other hand, in June 2018 the cost for a Sydney-London round-trip (a significantly longer route that also faces less competition than transatlantic flights) in first class on Qantas was (AU)$10,700 [2], an equivalent to (US)$7-8k now (depending on whether we take current or historical [3] exchange rates).
"First class" nowadays can mean different things on different airlines, routes, and equipment but prices are generally well south of $10k, with the possibility of paying a lot less if you're willing to do your research and are somewhat flexible. This was not an option at the time.
I think only the Concorde could compare to these 1939 prices: a NYC-London round-trip would be $13k if it still operated. [4] But other than that, the current first class offerings are less expensive.
1. https://data.bls.gov/cgi-bin/cpicalc.pl?cost1=650&year1=1939...
2. https://www.smh.com.au/money/planning-and-budgeting/the-cost...
3. https://www.rba.gov.au/statistics/historical-data.html#excha...
https://archive.org/details/secondworldwar00beev/page/709/mo...