Can MacBooks backup when in hibernation mode?
If your MacBook Air has flash storage, supports Power Nap and is connected to a power adapter at night, then it will back up to Time Machine when in sleep. If any of these criteria is not met, then the backup will not take place.

A firmware update is required for the late-2010 MacBook Air to support Power Nap. Make sure that all updates are installed in the Mac App Store and you can check for Power Nap functionality in System Preferences → Energy Saver → Enable Power Nap….

For more information on Power Nap, see:


OS X Yosemite: About Power Nap