When I go to the Alps/Spain I usually take spare brake pads, spare inner tubes, a spare chain, a spare rear derailleur and a spare derailleur hanger plus a spare pair of tyres and a decent tool kit, but I usually drive down so weight isn’t an issue.
If I was flying I’d probably take everything above but only one spare tyre and a smaller tool kit.
It’d be incredibly frustrating to go away on holiday and damage something on your bike on the first day and be unable to ride for the rest of the week. Whilst you can’t cover all eventualities sticky-out bits (derailleurs and hangers) and bits that wear (pads, chains and tyres) are quite often easy pickings for rougher terrain taken at higher speed, as quite often is the case in my experience of MTBing in Spain and the Alps. Indeed when I was in the Alps last year the guy I went with damaged two rear derailleurs and snapped two chains and by the end of the week my DH tyres were looking decidedly tired.