Mxsmanic wrote:
Michael Nouak writes:

As far as SIDs and STARs are concerned, more often than not
the main reason is noise abatement.

I'm surprised that noise abatement is still an issue. Modern
high-bypass turbofans are very quiet compared to their turbojet
ancestors of a few decades ago.

I work for a manufacturer of high-bypass turbofans and they're still
extremely loud. I also live next to one of the busiest airports in the
country. Believe me, there's not much difference between old and new.