An Airdale is one of, if not the, largest Terriers. They a not uncommon, boxy snot brown fore and aft with a black blanket, short curly to kinky hiar, about the size of a standard poodle. They are tough customers when trained to be. The guys out here that run corsing hounds on coyotes often use an airy or airy cross as a kill dog. They can be a bit sassy atimes but usually make a pretty good buddy.
When you take your lab along, all those times / places he hikes on are probably good spots for a scent post or scat plus urine set.