The Passbook app is the most intriguing new capability in iOS 6, but also a big question mark. The app is meant to store tickets -- airline tickets, movie tickets, and more -- so you can use your iPhone to check in to all sorts of venues from the convenience of a single app that has them all. (Passbook is not available on the iPad or iPod Touch.)
That sounds great, but for Passbook to be useful, ticket issuers need to get on board, and it's unclear how many will do so and when they might. So far, the good news is that American, Delta, and United have committed, so other firms -- not just airlines -- are likely to follow.