I have a Welsh Terrier (same color as the Airedale but smaller and a completely different breed). They are supposedly one of the oldest of the British terrier breeds, originating from the old English Black & Tan Terrier. And were used along with the Black & Tan and the Otterhound to develop the Airedale. Like the Airedale, they are “unique souls.” But I certainly would not recommend them for protection dogs. Although they can be quite territorial and can “flip the terrier switch” with the best of them, they are too small for protection against a determined attacker (Welshies are generally under 25 pounds).
If I was serious about a protection dog, I would go with a Doberman Pinscher or Belgian Malinois. They are tough dogs and quite serious about protecting their “pack” and although they are substantial enough to be a very formidable deterrent, they are not as massive as one of the Mastiff-descendants so are sometimes easier for ladies to manage.
And to stay on topic - does anyone know what kind of dog MB has? Is it at his Florida farm? I can imagine its complete and utter joy when it is finally reunited with MB!