WACO
I'm afraid you speak utter tosh.
BA, KLM, Lufthansa (and many more) are flogging around 747s in excess of 20 years old.
Delta operate many DC9s that are over 35 years old & American MD80s are 25+ years old.
Pontious cannot fly them all.
Ancient aircraft does not= lots of delays.
The Jet2 fleet are not excessively old, however, the Jet2 OTP should be better than it is.