The Inquirer, the Philadelphia Daily News and Philly.com ran a series of spoof airline advertisements yesterday that a spokesman said were meant to gauge their collective power "in generating awareness and traffic for, in this case, a brand that doesn't even exist."

The full- and partial-page ads for Derrie-Air, a fictitious environmentally friendly airline purporting to offer fares based on a passenger's weight, appeared 21 times in sections of The Inquirer, 15 times in the Daily News, and on the Philly.com home page.

Jay Devine, spokesman for Philadelphia Media Holdings L.L.C., owner of the newspapers and Web site, said the ads were also meant "to put a smile on people's faces."

The ads carry no disclaimer, but one does appear on the Web page to which readers are referred in the ads. It says, in part, "The Derrie-Air campaign is a fictitious advertising campaign created by Philadelphia Media Holdings to test the results of advertising in our print and online products and to stimulate discussion on a timely environmental topic of interest to all citizens."

Devine said the print ads carried no disclaimer because "our goal was to drive people to the Web site."

He said early results showed a "click-through" rate for the online ads of 1.25 percent, compared with a national click-through average of 0.05 percent. The advertisements were to appear yesterday only, he said.