[TylerE]

For that matter there are still plenty of DC-3s in active service, and those are all over 80 years old at this point. Not nearly as big a deal as it might sound - the biggest wear item on a commercial plane is actually cabin pressurization due to the long term fatigue characteristics of aluminum. DC=3s aren't pressurized.

[nradov]

I'm asking about changing policies for newly manufactured airliners, not specific airplanes that have already been built. No one has used a DC-3 for FAA Part 121 scheduled airline service in decades.

[TylerE]

There are a number in regular commercial use (including passenger flights) in Canada which is a very similar regulatory regime. There are multiple US operators of the Basler turboprop conversion.