Updated

Federal aviation regulators have given final approval to establish an enormous bomber training area over the Northern Plains.

U.S. Sen. John Thune of South Dakota said Tuesday that the Federal Aviation Administration approved a plan to expand the Powder River Training Complex over North Dakota, South Dakota, Montana and Wyoming. Spanning across nearly 35,000 square miles, it will be the largest training airspace over the continental U.S.

The airspace will be used by B-1 bombers at Ellsworth Air Force Base in South Dakota and B-52 bombers at Minot Air Force Base in North Dakota.

Thune says the expansion will help prevent the closure of Ellsworth, improve national security and save on fuel costs.

Critics say the bombers will disrupt rural communities and businesses, and scare livestock.