- where are your parents located?
- what kind of trip would they like? (cultural, mountains, shopping, skydiving, listening to time sharing proposals,...)
- how fast do you want them back (some place have only once ever week a flight out) ?
- should I suggest you places where cellphones don't work*, so you won't have to call everyday to inform (or you want an excellent internet connection, so that they babysit your kids via webcam)?
you are giving way too little info; we need to know about when, which continent (maybe they want virgin galactic (bookable with eurobonus [SAS which is *A]), are they old old, or fifties, their blood type, vaccines taken, previous convictions, and so on)
* satellite phones will still work unless its below ground.