Janice D'Aloia of Portland, Ore., has about 1.5 million frequent flier miles on United Airlines.
Chris Thomas, a marketing executive in Jacksonville, Fla., has more than 1.6 million miles on Delta Air Lines.
Both travelers -- very busy frequent fliers -- are also banking on retiring one day and are building up their miles now for use in a slower time of life.
For many business travelers, frequent flier miles are part of their nest egg along with their pension plans, their 401(k)s and their stock portfolios.
But there's a problem: These globe-trotters may be around a lot longer than the airlines that hold their frequent flier miles.
D'Aloia, 47, has been saving her miles for 10 years. As an information technology consultant, she flies every week and gets miles from purchases with her United Visa card and her Diner's Club card. "We want to have enough miles to have a few good trips when we retire," she said.
But like technology stock investments from the 1990s, the value of frequent flier miles is declining along with the health of the industry. Airfares have dropped considerably in recent years, decreasing the value of award miles. At the same time, many airlines have added numerous restrictions and fees to redeem miles.
"If you think of miles the same way you hold a stock, holding onto the miles for the long term is like holding onto a stock that has been losing value and looks as though it will continue to lose value as far out as the eye can see," said Tim Winship, editor and publisher of Frequentflier.com.
He advises travelers to use their miles today rather than save them for the future.
If an airline goes out of business, all may not be lost, however. The miles may survive -- on another carrier, possibly at less value than they originally had. The frequent flier database of a failing airline is often attractive to other carriers looking for dedicated travelers. When American Airlines acquired Trans World Airlines in 2001, American took over TWA's frequent flier program.
For determined savers, frequent flier miles can be passed on to one's descendants -- a practice that experts say is growing. Winship said airlines often want to see a copy of a will, as well as a death certificate.
Georgetown contractor Albert H. Wu, 43, plans to start using his miles when he retires in five years. He said he realizes the declining value and so he intends to use them as quickly as possible.
"I hoard things that I know have no value and I do realize that. It's like Monopoly money. But Monopoly money can't get you around the world in business class," Wu said.
Wu, who has 550,000 miles on Delta, has already discovered how changes in the industry can force changes in his retirement plans. He was hoping to redeem his miles for a round-trip, first-class ticket on the Concorde, which was operated by Air France, a Delta partner. Now that the Concorde no longer exists, he plans to "fly around the world several times in business class."
Ben Kuckens, who retired from Smith Barney last year, uses a computer spread sheet to keep track of his miles. The 67-year-old Los Altos, Calif., resident and his wife plan to use some of his 700,000 miles to fly to New Zealand and Russia next year. The couple just returned from Ireland and took a photography trip to Cambodia in April -- all on award miles.
Kuckens, who has most of his miles on American Airlines, said he has trouble booking awards flights because airlines have set so many restrictions. He says he has to book at least nine months in advance to get a flight.
Booking a retirement flight is harder than managing his retirement fund, Kuckens said. "The difficulty is getting the seats," he said. "My retirement fund is already pretty much set up."