yourfather,
Correct, a 20 year old aircraft isn't necessarily less safe than a 2 month old one.
Re fatigue, our engineers use many techniques to detect it. For starters, many parts are "life'd" that is, they have a set time period they can be installed. After that, replace. There's boroscopes, x-rays and other non destructive methods to check the components.
Fatigue in components is relatively easy to catch, fatigue in people, a lot harder.
Turbine Engines rarely flame out. 2 reasons. Too much ice ingestion (it has to be A LOT) or lack of fuel. When there's a risk of icing or in clouds, we turn on the engine anti ice system and turn on the igniters. Unlike a car (piston engine), we (turbines) don't need the igniters (spark plugs) on all the time.
I strongly advise you to seek out Qantas' Fear of Flying course. It is well worth it. I used to assist on it every now and then.
ladylily,
Yeah, Malaga is known for it's turbulence and is caused by the mountains nearby. 15 min is a long time but if there's another aircraft above then they cannot climb.
Yes, a reassuring word from the flight deck would be useful, but if they're below 10,000' and trying to deal with Spanish ATC (controllers) as well as monitor what's going on, they just might have been a bit busy.
Turbulence dangerous? Only if you try and do something really silly in it. Hence flying in a thunderstorm is unwise. (Big cause of delays in summer)
I don't like it. I do my best to get out of it ASAP.