I've driven a 13 year old VW polo since mid-December, I bought it with 56,500 miles and as of tonight I'm on 64,720 miles. Monday-Thursday it got 3 of us to Hull and back. The week before that it made it's second trip to Bristol (both of which from Newcastle)
She's sweet as a nut! Smooth as silk, like a gazelle when there's only me in it.
All I have to do is look after it, I try and fill up before the fuel light goes on, I keep the oil topped up as regularly as possible, and a few minor bits have been replaced because of wear and tear. I still get 40-45 mpg and I've never had any major problems.
My point is, yes it's an old car, but it really doesn't have very many miles on it and it is well looked after. Just like Jet2's aircraft. All airlines have to abide by the same laws and meet the same standards. Hence, I would have no problems getting on an aircraft 20, 30, 40 or more years of age.
That might just be me though, I have a sweet spot for older, more unique aircraft. I'd probably pick an LS 733/752 (or one of the first off the line, non wingletted 738's) over a TCX A321 or TOM 738 if I could.
Just an added note... Yes you might get a 30 year old 733 or 15 year old 738 if you fly LS from Newcastle. But if you fly TCX you could well get a 16 year old, Lithuanian A320... Just off lease to Cambodia. OR if you choose to fly TOM, you could well be landed with a 20 year old Slovak 737 400...
It's not just Jet2, and I don't think there's anything wrong with it at all
I mean... People pay hundreds of pounds for domestic flights with Eastern and could end up with a 20-25 year old jetstream!