I've been slow to pick up this post, more guests visiting.......
I'm basing this on Misha and all I've learnt from the Airedale group I'm a member of. I'd say protective not aggressive....but I can see why people would think that - they do want to interactive with every dog they see and just throw themselves at other dogs..Misha thinks every dog, cat and ant should be ready to play.
...they like to show their teeth a lot which scares some people - they snap them together when impatient, bored or just for their own private amusement. But I've never heard of one biting intentionally or being aggressive and I've seen a few people asking that, but I guess a bad owner could fix that
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They are pretty aloof with people they don't know, (irrates some people), but very loyal and loving to their owners. I've had many clashes of wills with Misha, as some of my posts show. But I'm as stubborn as her and it is starting to pay off - but you definitely need to match their strong character - or they will walk all over you (quite literally).
I've read some bark a lot, but equally many don't - so I think that is up to individual dog. Misha just barks at the door bell - and scares herself - but it is a good warning to strangers.
They are big diggers & apparently chewers - although Misha won't chew anything that hasn't been given to her - we are very lucky.
She has been very easy to train in that she learns quickly, but can be stubborn as anything. She is highly food motivated and too smart to admit that praise will do! This very short article sums it up
-http://www.airedaleterriers.org/articles/sit.html
Have to finish this Aire essay by admitting that I doubt I will be without an Airedale from now on - I am a complete Airehead!