Basically both Boeing and Douglas (and others) had various dual-prop planes that could be used for passenger service in the early 30s timeframe--of which the DC-3 is the best-known (and came a couple years after the plane in the article).
But were these modern airliners and which was the first in that class. <shrug>
Plus of course a few takes on all metal monoplanes with multiple engines and multiple rows of passenger seats in the 1920s, if those are the criteria for modernity...
Think there's a decent case for the Vickers Viscount in the early 1950s too, as the first airliner with a modern turboprop engine type, with speed and range and passenger experience (big pressurised cabin) comparable to small airliners still being built, unlike the 247 or DC-3.
But were these modern airliners and which was the first in that class. <shrug>