Airfares may be reasonable, and gas prices aren't killing us the way they were a year ago, but there's one travel essential that's bleeding Americans: car rentals.

The New York Times reports that compared to May 2008, the price for a rental car shot up by 73% last month. In June, they were up 63% compared to a year ago.

Those leaps are extraordinary for any product, and the reason is simple: The major renters have cut capacity, selling older stock and waiting to buy new cars. The airlines have done the same thing in order to stabilize what would otherwise be a dramatic collapse of airfares. Even though demand for rental cars has dropped by 15%, the supply of vehicles has plummeted by more.

The stuff they have is not only a little older than it was a year ago -- an average of 11-months-old, compared to 9-and-a-half months last year -- but it's also of a lower quality. Last week, on a trip to Orlando, I was dismayed to learn that none of the rental cars of my chosen company came with built-in XM Radio anymore. Last fall and early winter, on other trips to Orlando, my cars always came with satellite radio, and I loved it.

The clerk told me that their cars were delivered to them with six-month contracts, and all the XM-equipped cars had been phased out. There goes the biggest reason I had to choose that company.

But any competitive advantage lost by the car renters (and by XM -- seriously, what brilliant exec let that golden marketing opportunity wither?) has obviously been counterbalanced by higher rates.

All in all, my five-day rental cost around $500, whereas two years ago, a car could be had for as little as $30 a day.

Alamo Rent A Car announced a promotional sale that was supposed to be valid through July 18, but then, without alerting the same media outlets, it quietly and without explanation ended it nearly a month early. When I asked reps why, I was tersely told, "we experienced extremely high customer demand."

The Times had a few suggestions for whittling the rates down, and most of them boiled down to finding a rental desk far, far from an airport, such as in quiet suburbs, or ones run by mom-and-pop operations. Its suggestion of getting your car through promotions run by your airline is a direct contradiction of that recommendation, but for those of us who don't think it's an economical use to time to spend four hours after touchdown retrieving our wheels, it's probably the more workable plan.

The Times also suggested deal-sniffing websites such as FatWallet.com and CouponWinner.com, but frankly, given the complicated reservations systems the major renters use, I find that coupon codes work only intermittently.

An end may be in sight. Car rental companies are reporting that recent bookings have not been as lax as expected, so they are starting to put the gas on delayed new-car acquisitions. But for the time being, and certainly over the peak summer travel period, higher rates will win out.

It's a good thing that such plentiful and affordable public transportation options are available, otherwise traveling Americans would really find themselves over a barrel.