External Seagate Hard drive for Mac - Compatibility
As long as the drive connects to your MacBook Air via a connection protocol that the Air supports like Thunderbolt or USB 2 or USB 3 you can format the drive and use it with your Mac just fine.

To format an external hard drive on your Mac (paraphrased from here):


Connect the drive to your Mac
Open Applications &gt; Utilities &gt; Disk Utility
On the left hand side of Disk Utility you'll see a list of drives. Find your external drive and select it.
Select the Erase tab and choose Mac OS Extended (Journaled) for the format and give it a name
Press the Erase button to kick off the process. NOTE: This will erase everything currently on the hard drive!