It sounds like the USB drive doesn't have the drivers to boot the other macs. :-(
The fastest path forward is to simply erase install a basic Snow Leopard OS onto the failed macs. While this is happening, do download the 10.6.8 Combo update to your USB drive just in case it's needed.
Don't bother running the updates unless the Lion installer forces you to get to a higher version than your 10.6 installer delivered.
Once you boot into Snow Leopard - you can try again to mount the USB and execute the Lion upgrade package. I don't know if it runs well from the USB or needs to be copied to the internal boot drive.
There's a little uncertainty in my brain - so I don't want to write too much without making sure this makes sense to you.
As an alternative - you could try instead to transfer the recovery partition, but this may not be universal (include the drivers the older macs) either.
There is a step-by-step recipe here for copying any bootable volume to one file on a USB drive.
If you are curious or feel it's worth a shot, image the recovery partition from your Lion mac.
You should be able to boot from DVD and use disk utility to make an equivalent partition on the "non bootable" mac and drop the recovery data to get a minimal bootable system and avoid a full Snow Leopard install.
Unless you are familiar with Disk Utility and the steps to capture, the reinstall option might be more likely to succeed on first attempt. I certainly don't know if this partition is customized by Lion and not universal so I've made it an aside for the curious.
Sorry but I don't know of any other way to reinstall your lost data.
If you do want to download before installing, borrow someone else's Mac to
- Download Lion from the Mac App Store. The installer should show up in your Applications folder.
- Right-click on the installer and hit "Show Package Contents". Navigate to Contents > SharedSupport and look for a file called "InstallESD.dmg".
Open up Disk Utility and drag the DMG file into the left-hand sidebar. If you're burning it to a DVD, insert your DVD, select the disk image in the sidebar, and hit the "Burn" button. Skip down to the last step to use it.
If you want to burn Lion to a USB flash drive:
- plug it in and click on it in the left-hand sidebar in Disk Utility.
- Go to the Partition tab and select "1 Partition" from the dropdown menu. Choose "Mac OS Extended (Journaled) on the left.
- Hit the Options button under the partition table and choose "GUID Partition Table". You'll need this to make the drive bootable on a Mac. Hit the Apply button when you're done to format your drive (note: it will erase everything on the drive).
- Click on the "Restore" tab, choose the InstallESD.dmg file as the source and your flash drive as the destination. Hit the Apply button and it will create your bootable USB drive.
Connect your MBAir DVD drive and boot into OS X and hold the option key when you hear the startup chime. You can boot into your DVD or flash drive from there.
Best Answer
Assuming that the InstallESD.dmg is on the windows 7 computer:
*You might not be able to restore from an image that on the drive being restored. In which case use 2 USB drives (one to copy the InstallESD.dmg from the PC and one to restore it to and boot from) or:
ls /Volumesto find the location of your hard drive and USB drivecpto copy the InstallESD.dmg to you hard drive. (e.g.cp /Volumes/USBDrive/InstallESD.dmg /Volumes/Macintosh\ HD/, where you replace the paths with the ones found in step 2)Or if your USB CD drive can burn DVDs and you have a DVD, you could use the USB drive to copy from windows and then use the Macbook's Disk Utility to burn the image to the DVD. (or use the DVD to copy from the PC and use the USB drive to boot)