my brother is a licensed plumber (local) the joke between us is.... the 3 things a plumber needs to know...
1. $#!t rolls downhill.
2. NEVER chew your fingernails.
3. Payday is on friday.

all joking aside BOTH are good careers and alot of times are tied together.
Both will be physically demanding (you are 48...)

I agree with dodge about finding a company that covers all 3 (air /poop/power) and see what you like.

lots of my family have retired from the union with good pensions but with physical (shoulders/ knees/ back issues from pipefitting. my brother has LOTS of certs so he is always employed which is a big key no matter which field..... diversify as much as possible.

what was the field you were dislocated from???