Board Mathel's Flying Machine at the Gol'Bolar Quarry.
According to the plans you captured, the Dark Irons are planning a large-scale attack on the Ironforge Airfield! The council has moved most of our forces down into Dun Morogh to deal with the instability brought by the cataclysm, leaving our defenses weakened at the airfield.
We need a way to get you to the airfield quickly. Take the road back west toward Gol'Bolar Quarry and find Mathel Rustwrench. He should have a flying machine you can use. Go!