Why feel sad?
Every gutted airliner hulk is a tribute to the best mankind has to offer:
-The ingenuity to build it in the first place, and build it well enough where it can last for decades.
-The professionalism of every aircrew who ever flew her...three, four, five times a day for twenty, thirty, forty years...these aircraft cheated gravity and engaged safely in what is an essentially chaotic endeavour....flight. And the people up front in charge always got her home again. Safe & sound.
-Have you ever met someone you love at the airport? Had a big hug? Felt very happy to be home? Think of the millions of warm feelings these aircraft were responsible for. How many families did they take on holiday? How many business deals did they take people to? How many job interviews? How many college kids to spring break?
No, I don't feel sadness. These machines performed well, did their noble job, and made way for new ones.
All GOOD things....must come to an end.