FYI Sam2, AnnonymouscMember is so correct & on the ball. When I was young, everyone waited until after Tisha b’Ov to vacation, as the 3 weeks are time for introspection of our national loss/lack of Bais-haMikdosh.
Albeit technically there maybe nothing wrong in traveling & taking a vacation, it certainly doesn’t exhibit any atmosphere of truly feeling despondent over our lack/loss of Bais-haMikdosh.
Despite the numerous details of Halocho pertaining the 3 weeks, the bottom line is:- Are we feeling our loss? as is AnnonymouscMember.