The Stratoliner was a Boeing 307 with about 33 seats in normal configuration, developed from the B-17 for civilian transport use. It competed in the pre-war 4 engine market with the larger Douglas DC-4. TWA worked with Lockheed on the Constellation pre-war to replace the 307.
Note it says "only 4 hours and 21 minutes to Chicago."
Presumably, that would be from today's LaGuardia to Midway airports.
So yes, today's jets are faster, but by the time you travel to & from more distant airports, go through airport security on one end, and baggage claims on the other, how really much quicker is today's travel time?