I got elite status when I was 15 and never once was asked for ID getting into an MLL. My parents are european so by this age I helped myself very freely to the beers and hard alcohol but obviously not to the point of getting wasted in the MLL.
As for flights back in the lates 90s they were very relaxed with giving out alcoholic beverages. I presume if he looks decently dressed a few bevies won't be a problem, especially in J