Apple is expected to release an updated MacBook Air powered by Intel's latest ultra-low voltage Sandy Bridge processors any day now. Apple may in fact have the hardware ready to ship from its manufacturing partners in China, but it appears the company is waiting for the next version of Mac OS X to be finalized before launching the new version to the public. The same may also be true for Sandy Bridge-powered Mac minis and new Cinema Displays.

According to sources for AppleInsider, Apple management is "unwilling to usher the new [MacBook Air] models into the market with the current Mac OS X 10.6 Snow Leopard operating system." Instead, Apple is waiting for Lion to reach golden master status to ship the machines with Lion pre-installed. Apple is also waiting for Lion to launch a Sandy Bridge and Thunderbolt update to its Mac mini.

Apparently the reason for the wait is that Apple wants users to adopt Lion, with its support for Apple's new iCloud services, as quickly as possible. While anyone buying a new Mac after June 6 will qualify for a free upgrade to Lion, holding off on releasing one of its most hotly anticipated laptops will ensure that more users are using Lion as soon as the operating system is available.

Furthermore, Lion includes a number of features that will make Apple's diminutive ultraportables more appealing for mobile users. First and foremost is automated syncing of important data and documents with iCloud. Other features will enhance the MacBook Air's "instant-on" ability, including Auto Save and Auto Resume, and AirDrop will make it easier to share files wirelessly.

Apple said earlier this month that Lion would ship in July, so the wait for updated MacBook Airs and Mac minis shouldn't be more than a few weeks.