It's silly because we haven't contributed to the achievement in any way.

You contribute as a member of a civilized society that makes it all possible. The reason A350's aren't being built in Bangladesh isn't just the lack of monetary capital. It's the lack of social capital, in the form of functional institutions that enable some people to concentrate on things like next-generation airplanes.

To what rayiner said, I'll add that feeling part of something (the EU, in this case) is not silly - it's a basic human need. And if you feel part of something, it's also human to feel good for its successes and bad for its failures.

Well I find all manners of nationalistic pride kind of silly. Like someone said below, it's not like I did anything to make that happen, besides the taxes I'm paying.

The pride I'm feeling in this case is more a measure of the fact that Europe still produces great engineers and can sometimes cooperate to make great things happen. It's hope for the future.