HistoryLink: Boeing 307 Stratoliner Pressurized Airliner -- A Snapshot History

Here's a trivia question for you.

These days, speaking of an airliner, we call it cabin pressurization. In 1940, when it was first in use on commercial airlines, what was it called? Cabin what?

The answer to that question, plus more on the first high-altitude passenger jet airliner and on 1930s aviation research, can be found here. (HistoryLink, The Online Encyclopedia of Washington State History, File #3598.)

The prototype Boeing 307 Stratoliner first flew on December 31, 1938.

According to the linked article, in addition to cabin pressurization, the Boeing 307 Stratoliner also had "power boosted control surfaces and geared two-speed engine superchargers," making it very advanced for its day.