[CQ-Contest] How to log an air mobile station in ARRL-10 contest?

[Oliver Dröse]

Hi there,

I worked a station /am in a plane during the ARRL 10 m contest. He sent me a 
serial number as well as the IARU region he was flying in.

Now how do I log this contact? With serial number or region? The rules are clear 
concerning maritime mobile (/mm) operations but no mention concerning air 
mobile. And if with region which format to use? For region 2 just input "2" as 
the exchange or rather "R2"? How do you distinguish between as serial number and 
a region number?

To make it even more interesting: For maritime mobile contacts the IARU region 
sent is a multiplier. How about the air mobile station then?

Any advice?

Vy 73, Olli - DH8BQA