List of most produced aircraft
The Cessna 172 tops the list at 43,000 and counting.
Only 17,000+ Beechcraft Bonanzas have been built; but it has the longest production run of any aircraft, having been in production since 1947.
16,000 Bell UH-1s have been built, making it the most-produced helicopter.
The most-produced airliner was the Douglas DC-3, at 13,140.
The MiG-21 is the most-produced supersonic fighter.
I often wonder, in cases like this, whether there’s anything really meaningful about such long production runs.
I can’t claim to be an expert in aviation technology and development, but my question would be: how similar is a 2009 version to the 1947 version? And how much difference should there be before the term “continuous production” loses any real meaning.
It’s not just planes. Look at cars. The Chevy Impala has been in production since 1958, but the only thing that this car and this car really have in common is the Impala name. If you took all the badges off and asked someone with no prior knowledge, they’d be pretty hard-pressed to identify them as part of the same production run.
Airplanes are different from cars.
Here is a photo of a 1947 Beechcraft Bonanza, and here is a photo of a 1981 V-tail Bonanza. (Beechcraft discontinued the V-tail in 1982, but the Bonanza is still in production with the conventional tail.)
Here is a 1957 Cessna 172, and here is a photo of a 2009 Cessna 172.
As you can see, the airframes are basically the same. Of course there have been improvements over the decades, but airplane makers are a pretty conservative lot. If you’ve come up with a successful design, don’t mess with it. Better soundproofing, better, slightly more-powerful engines with a longer TBO, structural improvements, better interiors and panels, Bold New Graphics, and better instrumentation and systems are common. But the basic layout of the airframe is the same. You’ll notice that the 172 went from a ‘fastback’ design to one with a rear window. This happened in the early-'60s and has been the same since. Newer Bonanzas sport extra side windows.
Unlike cars, where their fundamental structures and body styles change over the years – sometimes quite rapidly – a 50-year-old 172 is still a 172. My dad had a 1968 Cessna 182 Skylane. We were flying it in the '90s and with the fresh paint job a lineman thought it was brand new.
Too late to edit.
Here’s a straight-tail Bonanza. Note that aside from the straight tail vs. the V-tail, they’re pretty much identical.
Fair enough. As i said, i’m no airplane expert. I wasn’t sure how much these planes changed over time.
Do you think someone who learned to fly in a 2009 Cessna or Beechcraft (and had never flown any other plane) could step into a 1950s model and immediately know how to fly it? And vice versa?
The v-tail looks cooler to me. What was the advantage to the v-tail design?
Here is a short Wiki page on V-tails.
A qualified ‘yes’. First, I should point out that the Cessna and the Beechcraft are very different aircraft. The Cessna is pretty basic, while the Beech is a high-performance aircraft. You’d need training and an endorsement to go from the Cessna to the Beech. (I would not have a problem gong from a Cessna 172 Skyhawk to a Beechcraft Musketeer, though.) Now to compare apples to apples.
I learned to fly in a 1970 Cessna 172 Skyhawk. (This one, in fact.) So I’ll go from there. In addition to '573 I’ve flown other 172s, from the '70s and '80s. They were all the same. A 2009 Cessna Skyhawk is likely going to have a glass panel. (Hey, if you’re going to spend a third of a million dollars on a new airplane, do you really want the old ‘steam gauges’?) So you’re going to have to learn the systems. The 1970 Skyhawk I learned in could deploy 40º of flaps. Newer ones are limited to 30º. You’ll have to take that into consideration. (I liked to land with the full 40º. It was dad’s plane, and I wanted to save his brakes. 
) But aside from the panel, a new Skyhawk will fly like an old one. Going from dad’s Skyhawk to a '57 172, I’d notice that aft visibility was less. Also, the '57 had a ‘Johnson bar’ (a long lever between the seats) to deploy the flaps. Later models were electric. Going from a 2009 model to an older one would probably be easy, as you’re likely to have trained in a model without the glass panel.
So yes, the same model aircraft from different years will fly the same and you can pretty much ‘just jump into one’; but you really need to go up with an instructor when things such as the instrumentation are so very different.
Instrument panels.
Here is the glass panel linked to in my previous post.
Here is a panel from a 172SP, which is the cheaper option than the 172SP glass panel above.
This panel looks like the one in dad’s Skyhawk, though his was an earlier model without the padded yokes.
Here’s a 1957 Cessna 172 panel. Note the Johnson bar on the floor, BTW.
The most produced jet airliner is the Boeing 737. According to the link there are over 1250 B737s airborne at any one time with one taking off or landing every 5 seconds on average.
How does it get around the pattern so fast? 
Would that include the military adapted C-47 Skytrain and Lisunov Li-2, or the Basler BT-67?
He asks, pretending he knows what he’s talking about.
I would assume that they are including military versions in the count, since they are the same airplane. The Lisunov Li-2 is counted, as it was license-built. Japanese ones are counted as well. But the Basler BT-6 wouldn’t be counted, since it is a retrofitted airframe.
Until recently, small plane manufacturers didn’t screw around with the engines either. They were based on 1930’s - 1940’s technology. It is really hard to get new engines approved in the U.S. so most manufacturers didn’t bother. There was a gigantic slump of small plane manufacturing in the 1980’s through the mid 1990’s. There are a lot more innovations today now that manufacturing has picked up again. Like ** Johnny LA** said, planes aren’t like cars. They don’t truly wear out because they are maintained so well and the airframes are incredibly strong and non-corrosive. The B-52 is the primary U.S. strategic bomber and the current planes were built in the early 1960’s and aren’t scheduled to retire until at least 2040 when they are about 80 years old. There are plenty of DC-3’s still in service around the world and many of those were built in the 1930’s.
Any list of aircraft production longevity should include the Beechcraft Model 18 (often just referred to as the Twin Beech). More than 9,000 produced from 1937 to 1970; and it remained recognizably the same airplane for its entire run. I’ve been trying to find pictures of the first and last year, but you just can’t tell how old the darn things are. I think it changed less than the Bonanza or the C-172.
And amazingly enough, only about 600 were ever built for civilian service. All the rest were under military contract.
I was going to mention that about the engines, but since the question was about aircraft models I decided not to. Not only is it very expensive to certify a new engine, it opens the companies up to ruinous lawsuits. If a pilot goes flying with open buckets of gasoline in the passenger seats and decides to make a cup of tea with his Svea stove and the plane blows up, you know that the engine manufacturer is going to be sued (and lose) because the engine manufacturer didn’t design the engine to not start when it detects that the pilot is loading open buckets of gasoline in the cockpit.
In the 1970s aircraft manufacturers built up to something like 15,000 or 17,000 per year. This, in spite of the first oil embargo and recession. In the 1980s a total production (of all manufacturers) of 2,000 aircraft was considered a good year.
I remember a lawsuit after a Cessna crashed. I don’t remember enough to find a cite, but as I recall there was a husband and wife aboard. They were both flight instructors and IFR certified. They flew into a thunderstorm and were subjected to severe up- and down-drafts and turbulence. They crashed. Their family sued Cessna (for not building an airplane that could fly into a T-storm) and Lycoming (alleging that the engine contributed to the crash). Even though the NTSB determined the engine was functioning normally, they won a judgement against Lycoming. Cessna had to pay $40 million. It wasn’t long after that that Cessna said, ‘You know what? To hell with it. If our customers are so stupid that they fly into T-storms, and then we get sued for it, we’re just not going to build piston-engine singles anymore. We’ll just sell to corporations, which have more sense.’
Until the General Aviation Revitalization Act of 1994, airplane makers were liable for all of their products. Theoretically, a maker could be sued for something that went wrong on an old aircraft even if the state of the art was not up to current standards when the aircraft was built. [Anally-derived example:] Suppose an owner lives near the sea and doesn’t take precautions against corrosion on his 1947 Bugsmasher 180 and there is a structural failure. Why didn’t the manufacturer design the airplane not to corrode, or use a modern (1990s) anti-corrosive coating when they built the aircraft? GARA limits liability to 18 years (another difference from cars!). Soon after that, more piston-engine singles (including Cessnas) started rolling off of the assembly lines – but nowhere near the numbers seen in the '70s.
It is my belief, which I’m sure people will dispute, that lawsuits killed aviation in the U.S. and drove up prices. In the 1960s a new Cessna 172 could be had for something like $9,000 to $12,000. (I’d have to do some searching.) In 1976 my dad bought his first plane, a six-year-old Cessna Skyhawk, for a little over $10,000. Today a 1970 Skyhawk will set you back over $40,000. With very few new airplanes being built, prices on the used market skyrocketed. I think that more expensive airplanes caused flying to become more expensive (and yes, there was the 1979 oil embargo too, and the rising fuel prices in the '80s) and fewer people were learning to fly. Fewer pilots meant fewer airplanes needed to be made. ISTM that while demand went down, supply went down more. In the early-'60s a brand-new 172 cost about $10,000. I don’t know what that is in 2009 dollars. Today a brand-new Skyhawk costs over $300,000.
It’s eighth on the 5,000 - 10,000 list.
Using the calculator on this site, $10,000 in 1962 money is worth anywhere from about $56,000 to $243,000 in today’s money, depending on which method you use to compute the difference.
$71,151.02 using the Consumer Price Index
$56,750.37 using the GDP deflator
$80,936.61 using the unskilled wage
$149,222.68 using the nominal GDP per capita
$243,589.48 using the relative share of GDP
mhendo: Thanks for that. Reading the descriptions, it looks like the CPI is the one that most closely applies in this case:
According to that, a new Cessna Skyhawk costs more than four times what it should.
You answered your own question there. 
Beech *claimed *it was to reduce weight and drag, but that was really negligible.
Well, remember that a new Skyhawk barely resembles a 45 year old one, or even one made before the production hiatus. A new one will have a full glass panel with all the IFR toys, a luxurious interior, “crashproof” seats, fuel injection … Sure, the basic airframe looks pretty much the same, but that’s a trivial part of the package.