DURHAM, N.C. — A struggle for air power is swirling between two Triangle hospitals - Duke University Health System and Wake Medical Center. Duke's Life Flight air-ambulance program is celebrating 20 years of service, while WakeMed is fighting to fly its own program.

When a deadly wreck shut down I-40 in Cary last October, Life Flight raced to the scene from Durham. That's because hospitals in Wake County are grounded.

"My reaction was 'Pardon me? There's no helicopter service here?'" said Dick Sears, the Holly Springs mayor.

Sears is leading an effort by the Wake County Mayors' Association to change state law, which prohibits two air-ambulance services within 60 miles of each other.

"Times have changed," Bill Atkinson, the WakeMed CEO, said. "The laws that we're dealing with are twenty-five years old and have not been modified in that time."

When Duke started flying, air ambulances were a risk. Now business is booming, and WakeMed wants in on the action.

Jeff Doucette, Life Flight's associate director, said the law not only protects Duke, but more importantly protects the public.

"What we're seeing in trends throughout the country is that in states that don't have laws like North Carolina," Doucette said, "third party operators are popping up all over the place."

These operators, Doucette said, play by a different set of rules.

"For-profit entities that are listening to scanner traffic and responding to accidents are doing things in this business we would consider to be unethical and unsafe," he said.

For now, Duke and UNC, which was grandfathered in, have the Triangle skies to themselves.

Duke's helicopters make 1,200 flights a year at a cost of $4,500 a flight.