area d is the largest area in zbw, covering almost half of the total airspace. area d overlies the eastern portions of massachusetts and new hampshire, and most of maine, as well as owning airspace extending around east of the coast. area d is responsible for descending and climbing traffic to and from boston logan, bangor international airport, portland international jetport, and all cape cod area airports. area d also includes some canadian airspace, mostly over new brunswick, but also a small area of quebec. the bulk of this is an artifact dating back to the cold war when loring air force base, a sac bomber base lying very close to the international border, was active. loring's circular terminal control area, that no longer exists, extended into new brunswick. this area was included with the rest of the tca in boston's area of responsibility. the base closed in 1994, but the canadian airspace has not been transferred back to canadian control.