Modern air travel is full of hassles, but one of the most arbitrary is the check-in. Why do I have to manually confirm that I'm flying when I've already paid for tickets and chosen seats? A few airlines around the world have eliminated that drudgery, but now it's coming to a major American airline. Delta has updated its iOS app (there's no update for its Android equivalent yet) with automatic check-in -- you'll get your boarding passes 24 hours before takeoff. In theory, the days of frantic last-minute check-ins are over.