(CNN) Sonna Anderson was enjoying a horseback ride through the Badlands in North Dakota in September 2017 when her horse, Cody, got spooked, jerked toward a fence and tripped on a cow track in the dirt. The horse rolled onto Anderson, who hit her head, briefly lost consciousness and broke three ribs.

The 911 transcript shows that an ambulance reached the 60-year-old judge from Bismarck within 20 minutes. Anderson was secured on a backboard and ready to go when an air ambulance, a helicopter with a medical crew, also landed at the scene. Anderson says her husband asked repeatedly whether the ground ambulance crew could take her by ground; there was a hospital less than an hour's drive away.

"But he was told that [the air ambulance] was necessary. They never told him why it was necessary or how much it cost, but they insisted I had to go by air ambulance," Anderson said. "But it's so odd there is nothing in the record that indicated it was time-sensitive or that I needed to be airlifted."

For that one helicopter ride, to a hospital farther away in Bismarck, records show that Valley Med Flight charged Anderson $54,727.26. Sanford Health Plan, her insurance, paid $13,697.73. That left Anderson with a $41,029.53 bill.

Valley Med Flight did not respond to requests for comment.

"It shocked me," Anderson said. "I kept thinking, 'my God.' I got a copy of the 911 and air ambulance report to see how long they actually spent with me, when really, it was only around 45 minutes. I wrote [the air ambulance company] a letter telling them that I thought it was all outrageous."

Shared outrage

about air ambulance bills have Anderson is not alone. CNN reached out to every state's insurance regulatory office. Nearly every one said it has heard from patients like Anderson, and complaintsabout air ambulance bills have "increased rapidly," according to the Mississippi commissioner of insurance.

Charges vary wildly. CNN saw bills ranging from nearly $34,000 to more than $533,000.

flight doubled between 2010 and 2014. Some states saw even bigger increases. New Mexico bills went up 229% between 2006 and 2015, a state 2017 federal investigation found that costs for an average air ambulanceflight doubled between 2010 and 2014. Some states saw even bigger increases. New Mexico bills went up 229% between 2006 and 2015, a state investigation found.

Each state's law varies in what can be disclosed about these complaints due to its interpretation of patient privacy. In some cases, CNN could see details about the patient's condition, how far and where they were flown, how much they were charged, how much insurance paid and the nature of the complaint. Some states released much less. Some would acknowledge only that there had been complaints. However, it's clear that these bills can be devastating for families.

One complaint sent to the Michigan insurance office says a family flew a dying relative home after he got sick in Arizona. To get him to a hospice in Michigan cost $547,725.

It cost another family $62,749.35 to fly a child with a malignant brain tumor from Wisconsin to Houston to see a specialist.

But these high prices aren't just for cross-country flights. An air ambulance transferred a man from a hospital in Winter Haven, Florida, to one in Orlando for tests, which would be a one-hour drive. The complaint to the Michigan insurance office about that Florida flight said the family faced a $31,253.33 bill.

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Emergency personnel requested another hospital-to-hospital transfer in Arkansas for an X-ray. It cost $37,850, according to a letter to the state insurance department.

"We carry insurance to avoid the catastrophic situations," wrote the man, whose name was redacted. "I don't see where the consumer is getting a fair shake in this deal."

The desire may be there for change, but nothing's worked.

The price of these flights is not regulated by Obamacare. Instead, they fall under the 1978 Airline Deregulation Act , which removed a state's ability to control airfares and routes long before air ambulances were common. October's Federal Aviation Reauthorization Act created a committee to address the problem, but it failed to design a definitive solution, experts say.

Air ambulances take off

Air ambulances became necessary out of a desperate need to save lives, but some question whether their value remains.

In 1966, civilian deaths from accidental injuries were "a public health problem second only to the ravages of ancient plagues or world wars," the National Academy of Sciences wrote at the time.

Air ambulances weren't a regular civilian option then, but when researchers discovered that soldiers wounded in the Vietnam War had better survival rates than California motorists injured in car accidents, the US government decided to fund two medical helicopter experiments in 1969. They were successful, and hospitals slowly started creating their own programs.

The golden hour

A 'cash cow'

the three largest air ambulance providers in the United States. Bain Capital bought Air Medical for $1 billion Demand for services wasn't the industry's only growth driver. The Balanced Budget Act of 1997 created a new fee schedule that was much more generous to independent operators and paid more for rural trips. Almost immediately, new companies entered the market. Private equity firms, not hospitals, now ownthe three largest air ambulance providers in the United States. Bain Capital bought Air Medical for $1 billion in 2010 and sold it five years later for $2 billion

As private companies got into the market, prices went up. Between 2010 and 2014, the median price that air ambulance companies charged Medicare doubled to nearly $30,000 a ride, according to a 2017 US Government Accountability Office investigation

"They have a cash cow on their hands," New Mexico state Rep. Liz Thomson said.

Thomson said a state analysis also found a 98% increase in the amount charged by air ambulance providers that weren't covered by insurance between 2009 and 2015. When patients travel on helicopters that are not in-network, insurance will cover little or nothing at all.

The Association of Air Medical Services says more firms are accepting insurance -- about a dozen announced that they were going in-network this year -- but still too many do not, Thomson said, and that can be a serious issue.

"If they aren't in a network, they don't have to adhere to the usual customary fees that insurance will pay," said Susan Rider, an employee benefits and human capital HR consultant with Gregory & Appel Insurance in Indianapolis. "They don't have to participate, so they don't, and then essentially, they can charge what they want."

In 2017, Thomson introduced a bill to cap reimbursement rates and let consumers off the hook for "balance bills," meaning what consumers owe above what insurance pays. The bill failed in the New Mexico Legislature, but she hopes to introduce it again.

The air ambulance industry packed the committee hearing room when Thomson introduced the bill, but it was not alone.

"I'm a Democrat and introduce a lot of legislation around patient protection, so I had a running joke that while I don't drink, I would drink a bottle of champagne if the [insurance?] industry ever stood up for any of my bills," Thomson said. "Sure enough, I needed to buy a bottle, because when the chair asked who was in favor of the bill, all these insurance people stood up and said, 'we are.' This practice is costing them a mint. It's outrageous."

Mike Castleberry , senior vice president of network services and business development for HealthSCOPE Benefits , a national firm that helps major companies manage health plans, said the costs for these services don't add up. "When you really get into the math, it starts to get embarrassing for the folks running those businesses," he said.

"We know what their fuel costs. We know how many hours they fly and how much it costs for a pilot," Castleberry said. "Add up all those factors, even if you give them a 20% profit on top of that, that's still not even half what they are charging me, which is more like 300 to 400 times what it actually costs to fly our customers. When I can go rent a private plane and put medical personnel on board for less than some of these bills, I know it shouldn't cost this much."

He also notes that a lot of patients whose bills the firm sees, who are told to take these flights, aren't trauma cases. "They are not for a wreck on the side of the road needing Level I trauma care," Castleberry said. "Only about 15% of the air ambulance charges we see involve those kind of accidents. The vast majority are patient transfers from one facility to the other."

Castleberry, who has clients across the country, said private operators aren't the only ones making money. "County governments and city hospitals [which can have their own air ambulance services] also see it as a revenue stream that supports their overall programs," he said.

The actual costs

The air medical transport industry argues that although single flights "may appear to be expensive," they are "very cost-effective" compared with building new rural specialty care or expanding ground ambulance capabilities.

Staffing an independent helicopter around the clock is expensive. It costs about $3 million to run an independent air medical base that does roughly 300 transports a year, said Chris Eastlee , vice president of government relations for the Association of Air Medical Services.

Some in the industry argue the problem is that the Centers for Medicare and Medicaid Services don't pay enough. They created current rates in 2002, based on an estimated 1998 cost pool, increasing reimbursement for inflation only. "It was never based on real cost collection," said Rick Sherlock , the association's ex-officio president and CEO.

About 70% to 80% of the patients whom air ambulances transport fall into these categories that the industry argue significantly underpay, like patients with Medicare. This payment is significantly less than the cost of the transportation, Sherlock said.

"Medicare pays about 60% of the cost of the flight; Medicaid pays 35% or less. Self-paid patients pay a few cents on the dollar, and that has led to a crisis of being able to sustain the service," Eastlee said. That means about 7 out of 10 of the association's flights are under-reimbursed, he said.

If the government reimburses the industry more, Sherlock said, "you eliminate the need to balance bill."

The insured pay the costs

Anderson, who was billed $54,727.26 total for her air ambulance rescue from the Badlands, got a letter from the air ambulance company's lawyer when she wrote to protest the price. HIs letter explains that 75% of that company's patients are covered by the government or have no insurance at all.

"This governmentally mandated cost shifting means that their cost per transport must be borne by others," the letter reads.

"In other words, I may not have had $54,000 worth of treatment, but essentially, they have to make up their costs somehow," Anderson said. "It's not fair at all."

"Some of these bills are pretty egregious, and these are consumers who have done everything right," Godfread said. "They have health insurance, they ask questions ahead of time, and often, they don't get to make the choice. It's often the hospital or the EMTs that decide to fly, but consumers are the ones left paying the bills, and there's really no way for consumers to protect themselves."

Andrei Courier learned that the hard way in June. He got a $41,063.78 bill after the in-network hospital where he took his son Jacob with breathing problems transferred the boy to an out-of-network hospital.

Jacob Courier's air ambulance hospital transfer cost $41,063.78.

"First, I could have driven to that other hospital faster," Courier said. "We also had tried to do everything in-network. We did everything right insurance-wise, but we still faced this huge bill."

His insurance company picked up $8,960.49 of the bill, that meant he would be left paying $32,103.29 out-of-pocket.

"We work hard, we pay our bills on time, and this is how we are repaid," Courier said. "It was so frustrating. That's money we would use for my son's college, not for a short helicopter ride."

Courier made multiple phone calls to the company, a lawyer and the Mississippi insurance commissioner. He learned that the state has a law that prevents balance billing , which is when insurance covers part of the bill and the patient owes the rest. Eventually, the cost of the flight was forgiven.

"I don't know what the insurance commissioner said to the company, but I finally got a call and was told they weren't going to balance bill me," Courier said, but he's still upset.

Med Trans Air Medical Transport, which ran the air ambulance that day, referred questions to the Association of Air Medical Services.

States try to help

Other state insurance offices say usually there's little they can do, beyond holding insurance companies to the letter of their policies. Most offices encourage patients to call with complaints.

Though states like Mississippi have balance billing protection, that tactic has had limited success elsewhere, as the courts have ruled that laws affecting air ambulances are federal, not state, jurisdiction.

North Dakota tried another approach. Its 2015 law required providers to disclose prices before the flight, upon request. Hospitals that referred a patient to the air ambulance company had to let the patient know the cost ahead of time unless the hospital determined that doing so would jeopardize their health or safety, in which case they would be exempt. The courts overturned that legislation, ruling that it was a federal matter.

North Dakota's 2017 legislation requires hospitals to notify patients in non-emergency situations if the helicopter takes their insurance. "We are optimistic. It is squarely in the claims process that we have the authority to regulate," Godfread said. "It will, however, likely be appealed all the way to the US Supreme Court."

The Association of Air Medical Services believes that the states can "help patients right now and help address the issue of balance billing and take patients out of the middle," Eastlee said. "Some insurance only covers a fraction of the price for those transports. We can work together."

The Office of Emergency Medical Services must establish a mechanism by January to give the patient a "good faith estimate." Virginia is trying another approach. Starting in March, its new law will require hospitals tell patients who don't have an "emergency medical condition" that they have a choice between air and ground transportation.The Office of Emergency Medical Services must establish a mechanism by January to give the patient a "good faith estimate."

Congress and the law

It will probably take an act of Congress to regulate the air ambulance industry. The FAA Reauthorization Act , passed in October, created an advisory committee with all the players involved who will focus on improving price transparency. The law gives the Department of Transportation and the Department of Health and Human Services authority to create new rules. It establishes a hotline and website to track complaints, and it creates an aviation consumer advocate position.

"It was important to me that we craft a solution that not only empowers consumers and patients but lays the groundwork for long-term solutions in the industry," said US Rep. Rob Woodall of Georgia, who added the air ambulance-specific language to the bill. "By creating an aviation consumer advocate, much like the taxpayer advocate for those with complaints against the IRS, my amendment provides a clear mechanism through which consumers can pursue enforcement or corrective actions -- which to this point had been absent in these situations."

The industry association said that it supports the FAA Reauthorization Act because it "enhanced consumer protection" and that the industry does want more transparency and accountability, Eastlee said, "but we also have to work to sustain the service."

Sherlock added, "the amendment does not address the underlying problem to reduce the patient's balance bill ."

For Anderson, Congress is too late. She took her own action. Instead of paying $41,029.53 out of pocket, she offered to settle for $4,100, on top of the $13,000 her insurance paid.

"I thought, I didn't want them to sue me and wanted to get this out of the way and thought 10% more was reasonable," Anderson said. For three months, she heard nothing from the company, so she wrote to withdraw her offer. The next month, the company offered to negotiate, documents show, but eventually, it accepted her offer.

Anderson's recovered from her injuries. And Cody, her horse, is OK. She brought him some extra feed to thank him, as the X-rays detected another medical issue she is now in treatment for. But the experience with the air ambulance still bothers her.

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"For a little more than 45 minutes of service, they were asking for more than what my surgeon charged. It's not fair," Anderson said. "I've since talked to other people who have been transported with no surprise bills, I think air ambulances can run in a fair manner, but the way it is currently done seems unfair and unreasonable. No one should feel shocked or panicked by a bill like this. No one ever."