Okay time to clear up some misocnception, when it comes to military technology, dwarves are in the fore-fromt. Now before I hear crying about gnome-tech take this into considreation.
Dwarves invented gun-powder, dwarves unvented guns, dwarves invented tanks. And while gnomes did invent the first flying machines the dwarves are also building tehir own flying machines and have been since the before the third war.
If you go on the wowpedia page for gnome-ish flying machines you get this
Dwarven tinkers improved on this technology after the Second War, first by creating dwarven gyrocopters and then later the upgraded dwarven flying machines.
Now if you go to the dwarven flying machine page you get
A dwarven improvement on helicopters built by their gnomish cousins, and their own Dwarven Gyrocopters, the flying machine is a heavily armed, flying gun platform. Thick armor protects the daredevil pilots who pilot the flying machines, but the armor also slows the vehicle considerably.
Perhaps the most unusual — or insane — warrior in the entire Alliance is the dwarven flying machine pilot. This captain of the skies performs everything from reconnaissance to bombing missions, fearing nothing (except perhaps a passing dragon).
Also it is mentioned on wowpedia that theer is quite a bit of dwarven engineering in the sky-ships as well.
So to sum it up, gnomes built the first flying machines. Dwarves then made their own version the gyrocopter. Dwarves then made the Dwarven flying machine during the 3rd war which was an upgrade to the gryrocopter as well as taking ideas from gnomish machines and improving them.
So dwarves have guns, mortars, tanks, gryphon riders, better militarily suited aircraft, arguably the finest forged arms and armor on azeorth, extremely tough and hardy soldiers as well as the strongest and most defensible City and Region (khaz'Modan).
Not to mention out of all the single races of the alliance they are arguably the largest and strongest military force.