Now boarding with Apple’s Passbook: two more major airlines

It looks like United Airlines (s ual) isn’t the only airline that will integrate boarding passes with Apple’s(s AAPL) new Passbook feature coming in iOS 6. Both American Airlines (s amr) and Delta Airlines (s dal) are likely on board as well, according to travel industry blog Skift.

Passbook, if you’ll recall, is an Apple-created app that can hold digital boarding passes, rail tickets, movie and sporting event tickets, hotel confirmation info, coupons, gift cards and more. We got a preview in June, which showed United and Amtrak tickets, as well as Starbucks (s sbux) digital gift cards and a Target (s tgt) reward card in use. Obviously the more businesses that integrate with Passbook, the more useful the feature will be.

It’s not intended to be just a central repository; it’s supposed to be a smart tool. Passbook is location-aware and time-sensitive: when you arrive at the airport or movie theater, your boarding pass or movie ticket will pop up on your iPhone screen.

Here’s what Skift found out about other airlines:

A spokesperson for American Airlines reveals it will be ‘rolling out an app update in the coming weeks in support of Passbook. In the meantime, customers can still access their mobile boarding passes in the current version of American’s mobile app.’

And, Delta is known to be actively working on supporting Passbook’s functionality for mobile boarding passes, although the airline wouldn’t talk about it publicly.

It’s likely there will be more in store though at next Wednesday’s iPhone 5 and iOS 6 official introduction in San Francisco. This report follows an earlier post Friday from Australian Business Traveller, which recounted a reader’s experience with Passbook and Virgin Australia. The reader, who was reportedly running the beta version of iOS 6, says he was prompted by the software to add his Virgin Australia boarding pass to Passbook — which could indicate the airline is planning to participate in the service as well.

There are already services like PassSource that will help any company create gift cards or coupons that will integrate with Passbook, but Apple is no doubt talking to mainstream consumer brands about direct integration. I’m betting we’re going to be hearing about a lot more big names next week.