You need to have a debit / credit card issued by a bank in Austria.
You need to have a billing address in Austria.
If you don't have a debit / credit card issued by a bank in Austria & a billing address in Austria, perhaps you can call to Apple Store in Austria and reserve the MacBook Air.
Get help and assistant from Apple directly, see -> Contact Apple for support and service
Contact Apple for support and service – Apple Support (UK)
-> Austria
-> call direct to 0800 220325
or
Call 1-800-MY-APPLE
Please note that the warranty only applies in the country where you made the purchase.
If something is wrong, you have to send the MacBook Air at your own expense to Austria.