For almost five years, 22-year-old Todd Blake has lived with an unusually persistent form of Hodgkin's lymphoma, which normally is curable.
Blake's treatment has included chemotherapy and two bone marrow transplants, with much of it provided in the college student's hometown of Jacksonville, Florida. But other treatments have required trips to cities as far away as Seattle.
Recently, after the discovery that his previous treatment regimen was no longer keeping his cancer in remission, Blake was offered the opportunity to participate in a clinical trial at the Center for Lymphoid Malignancies at Columbia University Medical Center in New York City.
That offer came with a catch: Blake would have to fly to New York once a week, for at least eight weeks. If the treatment works, he still would need to keep flying to New York about once a month—"endlessly," he noted—and if it doesn't work, he would begin a different trial that would require once-per-week trips.
"If I flew by myself every single time, it would probably be over $500 per trip when all is said and done," Blake said, noting the cost of a round-trip flight and ground transportation.
That was a prohibitive sum of money for Blake, he said.
But Columbia told Blake about a way to avoid those costs: the Corporate Angel Network, a charity that for 33 years has connected cancer patients who need to travel for their treatments with companies that have empty seats open on corporate jets they own.
Patients like Blake can catch a ride for free on those jets whenever seats are available, and the planes are flying to and from the patients' homes and treatment center cities. As a result, patients routinely rub elbows on those planes with corporate executives, including company CEOs, who are headed to the same destination.
Read MoreObamacare premiums being paid
On April 24, Blake became the 45,000th cancer patient to hitch a ride on a Corporate Angel Network-arranged flight when he flew from an airport in White Plains, New York, back home to Florida after getting treatment at Columbia.
The jet belonged to investment giant BNY Mellon, which has offered unused seats via CAN since the late 1980s. The company is one of 592 that are in the charity's current roster of jet seat donors.
Blake, who made the trip accompanied by his mother Nancy, said the nearly dozen Mellon employees who were on the flight "were all very nice...I had a really nice conversation with them."
Since then, CAN has paid for flights on commercial jets that Blake has taken to and from New York each week.
"I really wouldn't be able to continue with these trials endlessly without the aid of an organization like that," said Blake, who in addition to his studies runs a non-profit named the Live for Today Foundation, which helps young adult cancer patients.
"I just think it's amazing that these companies sign up to do this," said Blake. "It really says a lot about them. They don't have to do it, they opt into it, and that's what's really charming."
"We average about one flight per month, or about a dozen a year to support the organization," said BNY Mellon spokesman Ron Gruendl, who added that the corporation "is honored" to participate in CAN's program.
"Since our company leaders and board of directors approved our participation more than three decades ago, we've been able to witness first-hand that this service improves patients' chances of survival, as well as reduces their emotional stress, physical discomfort and financial burden," Gruendl said.
CAN's new executive director, Dick Koenig, said the charity's roster of jet-owning companies include about half of the Fortune 100 and more than 20 percent of the Fortune 500.
CAN's six-person staff and nearly 20 volunteers hook up patients needing air travel for treatment with available jets, which are tracked by location, destination, and seats available—information that is provided by the flight departments of corporations.
"About 6,000 requests a year come in, and about 2,800 get fulfilled," said Koenig, whose charity is based at the Westchester County Airport in White Plains. CAN spreads the word about its services via pro-bono ad space in media, communications by major cancer treatment centers, and "we're all over the Internet as well," Koenig said.
"We don't care whether you're rich or poor, you just have to have cancer," said Koenig, who is the former publisher of Flying magazine. Many of the patients, such as Blake, are traveling with relatives that are helping them get to and from treatment, and their travel is also provided by CAN.
The charity also has connections with ground travel companies, and hotels that offer discounts to cancer patients. In addition to flights on corporation's jets, CAN also receives donated flight space from owners of planes operated NetJets, who can gift their unused hourly allotments.
CAN's focus on cancer patient stems from its origin. The charity was started in 1981 by two cancer survivors, a man named Jay Weinberg and a woman named Pat Blum, who had a friend in the aviation business, Leonard Greene, founder of Safe Flight Instrument.
One day, "They were sitting around, looking at all these corporate jets, and said, 'Gosh, look at all those seats,' " Koenig said.
Greene made the first Corporate Angel Network flight in December 1981, personally flying a patient receiving treatment in New York home for Christmas in Detroit.
Saving cancer patients and their traveling companions plane fare is a primary benefit of CAN, but the program has other benefits. Flying on a corporate jet means that patients avoid an often lengthy, tiring process of checking in for a commercial flight and having to clear security, Koenig noted. Another benefit is reducing the number of people that a patient comes into contact with on a flight—which in turns reduces the potential for infection.
"What they often have is an immune system that's been pretty well battered," Koenig said.
Brian Kushner, an pediatric oncologist at Memorial Sloan Kettering Hospital in New York—the world's oldest and largest cancer-treatment center—said that many of his very young patients "make great use of Corporate Angel Network" to fly to the Big Apple from around the U.S. He called the charity "wonderful."
"It's very beneficial, because it's not easy flying around the country to get places with a young child," Kushner said. "It's a major undertaking."
He said that Sloan Kettering's social support system informs patients and their parents of the option of flights provided by CAN.
"You just see a big smile on their face when you mention it to them," Kushner said. "Many times I heard people telling me they were with the CEO on a flight, having a good time, playing with their four-year-old child."
—By CNBC's Dan Mangan.