What are the most produced airplanes ever?
Browsing the web, I found several contenders:
Cessna 172 Skyhawk as most produced plane over all, Messerschmidt 109 for fighter planes and the Boeing 737 as most produced jetplane.
Figures vary from site to site, though. Especially the Me 109 listing seems fishy - what about the P-47 Thunderbolt, or the Il-2 Sturmovik?
What’s the Straight Dope, aviation buffs?
This is a list that should answer your question.
Yes, the Messerschmitt Bf 109 listing is fishy but not that far of.
The point to remember about the 109 is they started making them in around 1935 (going from memory here) and were still producing them into late 1944.
By contrast, the P47 was first produced in around 1942 (memory again).
The US had a much higher rate of production per design, but for much shorter durations.
The Antonov An-2 has been in production since 1947, longer than any other airplane, altough it doesn´t beat the Cessna 172 in numbers; AFAIK about 15000 An-2s where produced.