How do I restore system MacBook Air?

This KB article has a link to a download you can use to create your own recovery USB flash drive:

http://support.apple.com/kb/DL1433

Yes, there's a very easy way around. Get an external USB hard drive. (They're cheap). Then clone your internal drive to the external usb drive using a program like Carbon Copy Cloner.

http://www.bombich.com/

This gives you the option to boot from your clone and restore it to the internal drive.

Your only other option is to purchase the Apple USB Lion flash drive installer - $69.00. Otherwise, you would do an Internet restore:

OS X Lion- About Lion Recovery

You can also create a small USB flash drive Recovery HD: OS X Lion: About Lion Recovery Disk Assistant.

If you are willing to make the effort it is possible to download the Lion installer used for your computer: Downloading Hardware Specific Lion Installers. From that you can create your own bootable Lion installer:

Make Your Own Lion Installer

1. After downloading Lion you must first save the Install Mac OS X Lion application.

2. Get a USB flash drive that is at least 8 GBs. Prep this flash drive as follows:

1. Open Disk Utility in your Utilities folder.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, set the partition scheme to GUID then click on the OK button. Click on the Partition button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.

3. Locate the saved Lion installer in your Downloads folder. CTRL- or RIGHT-click on the installer and select Show Package Contents from the contextual menu. Double-click on the Contents folder to open it. Double-click on the SharedSupport folder. In this folder you will see a disc image named InstallESD.dmg.

4. Plug in your freshly prepared USB flash drive. You are going to clone the InstallESD.dmg disc image to the flash drive as follows:

1. Open Disk Utility.
2. Select the USB flash drive from the left side list.
3. Click on the Restore tab in the DU main window.
4. Check the box labeled Erase destination.
5. Select the USB flash drive volume from the left side list and drag it to the Destination entry field.
6. Drag the InstallESD.dmg disc image file into the Source entry field.
7. Double-check you got it right, then click on the Restore button.

When the clone is completed you have a fully bootable Lion installer that you can use without having to re-download Lion.