My son subscribes to the magazine "Airliner" which I inherit after he gets done reading it. Its a very colorful magazine showing aircraft used by airline companies throughout the world. Which brings up a question: Can anyone quickly identify variants of the following aircraft. Boeing 737 (4-800), Boeing 767s, 777, Airbus 319, 320, 330. What are its noteworthy identifying features?

Bubblehead

Break down of the 737 is rather easy.

Thinks of ALL the variants as models introduces in three difference eras

First in the 60's came the 737-100 and the 200. Where the -200 was the bigger of them two, and no doubt the most popular one. The -200 made the 737 to what it is today. Both of the 100/200 has the cigarr-shaped JT8D engines from Pratt and Whitney.

Then in the early 80's came the 2nd batch of 737's, with new engines, as the most significant change. The CFM56 engines was much bigger and could not be hung below the wings, but instead had to be canterlevered out ahead of the wings leading edge.

To solve the ground clearance issue, the lower section of the nacelle was slightly flattened (hence the name "flat bottom engines". The cockpit also got a major upgrade in avioncis.  A semi - glasscockpit, similar to those in the larger 757/767 were introduced.
The 2nd generation were the 300/400/500. The -400 is the longest one, 500 the shortest

Then in the mid 90's, boeing launched the 3rd "Next generation" 737's. The wings got larger, engines got stronger (still the same flat bottom CFM56's, just newer versions) and landing gear was re-designed, just to name a few things. The cockpit was further upgraded to a fully state-of-the-art glass cockpit, found on the 777's.
the NG's are the 600/700/800/900. (shorter-longer order)

The Airbus family of A318-321 is just a matter of lenght. The shortest member is infact the A318, which is REALLY short! A321 is the longest one.
Their range and payload capabilities is off course different, just as the 737 versions but that is not visible to eye now is it?

the A330/340 are larger widebody versions. 330 has 2 engines and the 340 has 4. The cockpit is almost identical to each other, even to the smaller A32x series. This allows pilots to transition from a  smaller airbus to the larger one in just 8 days...normally for other aircrafts it takes 25
From A330 to a 340 it only takes 3 days, while going from a A340 to an A330 just equires 1 day of training  
This is called CCQ, oir Cross Crew Qualification, very typical for the Airbus family.

allright, that's enough babble from me  

Edit: AS the thread is in the "screenshot forums", maybe you wanted us to show pictures  ???
D'OH!  

the nose shape is the quickest way to tell them apart.
Personally i have found though the only planes to have a truely distinctive nose even the most amature of spotters could pick out are the DC10 MD11 and 747's
in terms of wide bodys the winglets are the next best way. Boeing tends to have a more curved nose that runs quite smoothly with only a small join between the cockpit windows and the nose itself. the Airbus tend to have a steeper window with a pointy nose. Well except the newer 340's but its impossible to get those mixed up with the 747s

This will help you out on your journey

This is a 737
http://www.airliners.net/open.file/616781/M/

This is a Airbus A32X series
http://www.airliners.net/open.file/577411/L/


On start up
http://www.airliners.net/open.file/473034/M/