A far more common acronym for luxury is "Lux", than "Lx". As you've mentioned too, super niche...financially well off people only. Chartered flights / first class seats are thousands, tens of thousands (depending on the destination / flight time etc) per flight...
All things considered, I don't like your domain, sadly. As said, super niche, not the most common acronym (lux)...its a struggle for me. Someone previously attempted lxdata.com (maybe this idea was "Luxury Data", who knows), but it fetched $60. Optimistic view: Take a shot between $49 - $199, otherwise drop