I’m not thrown off understanding “trip in vain”, but I dislike such poor writing. Maybe it doesn’t bother others, but the multiple parsing options, need for a single assumption of interpretation and general awkwardness interrupt reading for me.

if it actually said “you’re not going to make the meeting, and so your trip will have been in vain” it would be crystal clear. But is says “Tom was supposed to head into the meeting three hours after the flight is landed.” If the plane is delayed an hour.....he’d still have two hours to get to his meeting....see how…