[spenczar5]

Do you mean no two individual planes? Like two 767s made a month apart, do you mean they literally would have different requirements?

[WalterBright]

Yes. There are constant changes to the design to improve reliability, performance, and fix problems, and the airlines change their requirements constantly.

[numpad0]

Neat little detail of the world Wikipedia once told me: the 00 suffix of classic Boeing planes, dropped in 2016, was substituted with Boeing assigned customer code on registration documents. e.g. a PAN AM 773-300 would have been 777-321, an Air Berlin Jetfoil would have been 929-16J, and so on.

1: https://en.wikipedia.org/wiki/List_of_Boeing_customer_codes

[ponector]

I think they means that airplanes are made in different versions, catered to particular airline. Also planes are constantly updated.

Two 767 made few months apart will have initial difference, like two different versions of java 8 SDK.

[MBCook]

I think they meant a 737-400 is different from a 737-500 is different from a 787 and a AirBus 320 and a MD-80 and…

Every single model is somewhat bespoke. There’s common components but each ends up having its own special problems in a way I assume different car models in a common platform (or two small SUVs from competing manufacturers) just don’t.