I agree with Peggy that jeans are jeans - and it's too subjective to say what's appropriate (expensive designer ones are ok but not the "new" torn ones)?

But shorts? I don't travel (eg fly) in shorts but usually wear jeans nowadays (usually "designer" ones - mostly Hugo Boss with some Zegna, Armani, Diesel - which I don't think would be appropriate for an evening on a cruise unlike the rest of them).

Besides I don't really think that the typical Regent cruiser wears shorts flying - even the Caribbean since those cruises are mostly in winter and home is probably a cold(er) place.