To save fuel, volunteer pilot Bill Davidson now packs more than one sick passenger onto his shiny six-seat Piper Malibu airplane when he makes a hospital run.
So, on a recent afternoon flight from Houston back to Denton, 19-month-old Marisol Salas, who suffers from a nerve disorder called brachial plexus, sat across from Lenore Kinzenbaw, a 58-year-old woman with breast cancer. Both Marisol and Ms. Kinzenbaw had needed a flight to Houston hospitals for treatment. And Angel Flight - a free Addison-based transportation service provided by pilots flying their own planes and often buying the gas - was their most comfortable and affordable option.
High fuel prices, however, have made it more expensive for these pilots to fill up their planes, and Angel Flight's staff is worried it will lose the kindhearted services of pilots like Mr. Davidson.
It has already turned away 120 patients this year - one of the highest totals in the charity's 16-year history. Eleven patients had to be told "no" in June, the largest monthly number in recent memory, said Cindy Palmer, Angel Flight's director of events.
"You sure hate to call the mother of a cancer baby saying we can't give you a ride," Ms. Palmer said. For patients, these free flights can be the only alternative to either a crammed ride on a commercial flight - which might be hard for them to afford or even get to - or a long, uncomfortable ride in a car. Such trips can be especially difficult for small children and their moms or dads.
Some cancellations, of course, are due to weather. And some patients die before their scheduled flight.
But the vast majority of cancellations come because the organization can't find a pilot to fly, said Shireen Pitassi, Angel Flight's lead mission coordinator. And those are becoming more common.
"I feel that a lot of them are having issues with the cost of fuel, but they're too proud to talk about it," Ms. Pitassi said.
That being said, these pilots are hardly poor; some have seven-figure incomes, Ms. Palmer said. They fly because they can afford it.
"It's pretty expensive," Mr. Davidson, the 50-year-old owner of a commercial real estate firm in Lewisville, said of his volunteer assignments. "But flying already is an expensive habit."
More expensive than a landlubber cruising in his Lexus might think. Many small planes use a high-octane fuel called Avgas, an industry word derived from "aviation gasoline." Avgas grades are distinguished by their high octane rating - an indication of how quickly the fuel burns. Airplanes need the more expensive higher-octane gas because it burns slower and more controlled.
For his Continental 550 engine with its twin turbo charger, Mr. Davidson uses Avgas 100 LL - translation: 100-octane gas with low lead.
The First Air gas station in Addison sells Avgas 100 LL for $6.15 a gallon. (And you thought $3 gas was bad.) A year ago, that aviation grade fluctuated between $3 and $4 a gallon.
It takes 140 gallons to fill up Mr. Davidson's tank, at a cost of more than $800.
Then he flies 250 miles an hour and burns, on average, 20 gallons an hour. That's more than $120 out of his pocket for each hour in the air.
"My fuel economy is much like that of a large SUV," working out to the equivalent of 12 to 13 miles per gallon, Mr. Davidson said. "I'm just much faster."
The volunteer pilots used to get discounts when filling up their planes, a courtesy many gas stations extended because of the nature of the pilots' missions.
But higher prices have ended many of those pricing breaks, Mr. Davidson said and First Air employee confirmed.
So, Mr. Davidson now turns what used to be three short trips into one six-hour, 1,000-mile run. That saves on the gas needed for taking off and climbing to higher altitudes.
Of course, it also adds to the time involved for the patients loading up and means a more crowded plane.
On the recent flight from Houston, Ms. Kinzenbaw, the breast cancer patient from Lubbock, sat quietly while little Marisol, who lives with her family in Denton, tended to get fussy, carried on conversations with the clouds and shouted at landmarks down below.
"But it's [still] worth it," Mr. Davidson said. "Some of them can't cope too well on a 737 [airplane] in a middle seat."
Marisol's July 18 flight with her mother, Maria Torres, was her third trip, using six different Angel Flight pilots.
She has another appointment this Wednesday with Dr. Rahul Nath at the Texas Nerve & Paralysis Institute in Houston. Dr. Nath is widely considered one of the best in the field at treating brachial plexus, a condition often caused by trauma during birth.
At 6:30 p.m. on December 7, 2005, as Ms. Torres was giving birth to Marisol, the baby's head came out but her left shoulder got stuck, straining nerves under her armpit. "I knew something was wrong when the two doctors in the room quickly turned into eight," Ms. Torres recalls.
Now Marisol can't raise her left arm above her head. Without the full use of that arm, the little girl was never able to crawl. "She'd just scoot around, like a cute little monkey," Ms. Torres said.
"She'll never be able to do extreme sports. So we're maybe looking at a future pianist," said Ms. Torres.
Marisol, who has a crush on "Shrek" and cries when her doll of the animated character is missing, already takes Botox regularly. The $500-a-bottle serum is used to weaken her left triceps, which are overpowering her biceps.
But the problem could have been worse. If nerves in Marisol's neck were pulled during delivery, it might have resulted in brain damage. For that, Ms. Torres said she's grateful.
During this week's visit, Dr. Nath plans to perform surgery on Marisol to fix her misaligned shoulder bones.
Ms. Torres had to fight with Medicaid to allow her daughter to see Dr. Nath rather than go to a Boston hospital the government health program preferred. Treatment in Boston would probably have meant costly commercial flights for the family of modest means.
Once, Ms. Torres and her husband, Mitchell Salas, tried a commercial flight for the Houston trip, but the comments from other passengers - though not intended to harm - hurt Ms. Torres' feelings. After seeing the occupational therapy tape, they would ask whether Marisol fell and broke her arm - or suffered abuse.
Also, the metal splints Marisol often wears made it difficult going through airport metal detectors. Angel Flight allows patients to board at smaller regional airports, which are not as apt to have long safety-screening lines.
Every pilot interviewed for this story said he has no intention of landing his Angel Flight career. (They said they may, however, cut back on the number of missions they accept.)
And there will always be pilots like 54-year-old Michael Montgomery. High gas prices are mostly irrelevant - and sometimes welcome - for the president of Trek Resources Inc., a Dallas-based oil and gas exploration and development company.
"I get an opportunity to fly and help people at the same time," said Mr. Montgomery, an Angel Flight pilot with a $325,000 Beech Bonanza A36 airplane.
Mr. Montgomery counts himself as one of the lucky ones in life - someone with the health and the means to do something he loves, while helping someone else through a difficult time.
