At a meeting back in the 1930s, a professor of aerodynamics at the Massachusetts Institute of Technology named Ed Warner was told that Pan Am was developing a new 39-seat airplane. Warner scoffed at the idea, and scrawled some mathematical equations on a blackboard to show that it couldn’t be done. “There,” he said, “that proves it.”

I don’t know much about aerodynamics, but I’m pretty sure Warner was right. Any perfectly sane person can see that planes shouldn’t fly, whether they have 39 seats or — in the case of the new Airbus 380 configured for all-economy class — 853 seats. You can talk all you want about “lift.” All I hear is “fairy dust.”

But to walk through the doors of a modern airport is to enter into a world of wonders, where normal rules and laws don’t hold sway. And it’s not just the laws of gravity that have been repealed here. Many economic laws don’t apply, either: A four-day car rental is more than a seven-day rental. A one-way trip is more than a round trip. A 45-minute flight to a small airport in the next state costs more than flying clear across the country. Amazing and weird! Just those old roadside attractions touting freakish quirks of magnetism.

Then there’s the boarding pass I hold in my hand at the T.S.A. portcullis. This is where our power of make-believe needs to be strongest. We present our IDs and boarding passes to the pre-screener, who studies them for minor discrepancies with a gravity suggesting that our documents are the sole barrier keeping Islamo-Fascists out of the cockpit.

We all go along with it. Never mind that my “boarding pass” is something that I printed out from my computer the night before — in fact, the sort of thing easily ginned up by a moderately adept 12-year-old with Photoshop. (Last year a graduate student created an online boarding pass generator so that anyone could print out a fake boarding pass with a few clicks of a mouse. The site vanished after the creator was visited by unamused F.B.I. agents.)

Of course, the boarding-pass-and-ID-please hokey-pokey — the vanguard to the more sensible x-ray machines, metal detectors and explosive sniffers — isn’t really for national security. It’s for the airline’s economic security. This pre-screening is largely to ensure that we haven’t engaged in anything outlandish — like capitalism — by selling our tickets to someone else.

The airline ticket is a curious beast. It’s yours and yours alone, and unlike a ticket for a music or sports event, it can’t be sold or even given away. You hand it to someone else and it turns to dust. You can rebook or get credit for a future flight through the airline, but unless you’ve paid the top fare the exchange costs are hefty — typically about $100 per person.

Being locked into a travel schedule weeks in advance is disturbingly medieval in our fast-paced age, where we alter plans on a moment’s notice. Why can’t we sell our tickets if we decide today we’d rather be in Helsinki than Helena for Christmas?

Airlines say the restrictions are to maintain order and to prevent speculators from buying up all those desirable Helsinki tickets then selling them at a premium later. Possibly. But the larger reason is certainly that airlines make tidy millions on those $100 change requests.

Some lurching efforts have been made to create a sort of Stub Hub of the skies, a legal and equitable online secondary market. In 2001 FairAir.com went live, offering travelers the ability to resell tickets on several small carriers plus limited routes served by Northwest Airlines with fees starting at $9.95. Don’t bother looking for it. The site closed less than two months after it launched.

Airlines, predictably, saw little reason to give up their change fees just to make air travel more convenient for the flying public.

I hope airlines will revisit this — I’m convinced there are ways of doing this without their losing significant revenue. One possible model might be to mimic sports teams by having airlines establish their own reselling networks online. This not only allows the airlines to recapture a slice of subsequent sales, but guarantees that tickets won’t be fraudulent.

So someone with an unwanted Northwestern ticket, for instance, could sell it on the Northwestern Web site for flat fee — say $10. Sellers could set the price — perhaps capped at no more than 25 percent above what they paid to discourage speculators — and the airline would charge buyers another $10 to purchase. They could take a cut of the sale as well. While that still may be less than the $100 they now pocket, I’d wager they’d more than make it up in volume as relieved passengers rush to redeem their tickets to Helena without major penalties. And think of the goodwill — something airlines could use a bit of just now.

An organized secondary market for tickets has a certain amount of economic logic to it. Which means, like the 39-seat plane, I’m pretty sure it won’t fly.