After watching National Geographic's MegaStructures series, I was surprised how fast large projects are completed. Once the preliminary work (design, specifications, etc.) is done on paper, the realization itself of huge projects take just a few years or sometimes a few months.
For example, Airbus A380 "formally launched on Dec. 19, 2000", and "in the Early March, 2005", the aircraft was already tested. The same goes for huge oil tankers, skyscrapers, etc.
Comparing this to the delays in software industry, I can't help wondering why most IT projects are so slow, or more precisely, why they cannot be as fast and faultless, at the same scale, given enough people?
Projects such as the Airbus A380 present both:
Major unforeseen risks: while this is not the first aircraft built, it still pushes the limits of the technology and things which worked well for smaller airliners may not work for the larger one due to physical constraints; in the same way, new technologies are used which were not used yet, because for example they were not available in 1969 when Boeing 747 was done.
Risks related to human resources and management in general: people quitting in the middle of the project, inability to reach a person because she's on vacation, ordinary human errors, etc.
With those risks, people still achieve projects like those large airliners in a very short period of time, and despite the delivery delays, those projects are still hugely successful and of a high quality.
When it comes to software development, the projects are hardly as large and complicated as an airliner (both technically and in terms of management), and have slightly less unforeseen risks from the real world.
Still, most IT projects are slow and late, and adding more developers to the project is not a solution (going from a team of ten developer to two thousand will sometimes allow to deliver the project faster, sometimes not, and sometimes will only harm the project and increase the risk of not finishing it at all).
Those which are still delivered may often contain a lot of bugs, requiring consecutive service packs and regular updates (imagine "installing updates" on every Airbus A380 twice per week to patch the bugs in the original product and prevent the aircraft from crashing).
How can such differences be explained? Is it due exclusively to the fact that software development industry is too young to be able to manage thousands of people on a single project in order to deliver large scale, nearly faultless products very fast?