Airlines have already begun supporting mobile boarding passes for Passbook ahead of the launch of iOS 6.

According to Australian Business Traveler, a reader was able to load his boarding pass into Passbook by checking into his Virgin Australia flight on an iPhone running iOS 6.

AusBT reader Shaun Lorrain checked in for a Virgin Australia flight using the airline’s mobile website on his iPhone, which is running a developer preview edition of iOS 6 and this is what he saw (see image below).

Yes, iOS 6 detected the mobile checkin and offered to save the boarding pass into Shaun’s Passbook account.

The popup message came from the airline itself which means that airlines will be able to roll out support for Passbook as soon as they are ready.