WASHINGTON (AP) _ When A. C. Pheil paid $400 to become the nation's first scheduled airline passenger in 1914 he spanned travel history _ three decades earlier he had arrived in Florida on a covered wagon.

Thursday, Pheil's grandchildren were honored by a U.S. airline industry anticipating its 10 billionth rider.

``Now we have some credibility,'' said Peter Pheil of Chesterfield, S.C. The ceremony, sponsored by the Air Transport Association, vindicates a lot of old playground arguments when others didn't believe his grandfather had been first to fly, he said.

The nation's 10 billionth passenger will fly sometime in the next week, but transport association President Carol Hallett said the individual may not be identified until sometime later.

The industry took the occasion to bring leaders of the major airlines to Capitol Hill to lobby for repeal of a 4.3-cent-per-gallon tax on aviation fuel, scheduled to take effect Oct. 1.

And it collected at least one big ally, House Speaker Newt Gingrich, R-Ga., who said he opposes the new taxes, which he said could drive some airlines out of business.

``I'm committed ... to find a way to postpone or cancel this tax increase,'' Gingrich said to hearty applause from the audience of airline officials.

The airline industry has lost billions of dollars in recent years and the tax would just be an added cost, said John Dasburg of Northwest Airlines, stressing that competition prevents the airlines from just passing the increase along to flyers.

Joining Peter Pheil, an apparel marketing executive, were his cousins, William Pheil of Timonium, Md., and Betsy Pheil of St. Petersburg, Fla.

Peter Pheil said his grandfather probably never flew again after that first 21-mile trip across Tampa Bay, but once was enough for him to go down in history.

A.C. Pheil, a former mayor of St. Petersburg, bid $400 in an auction for the right to be first, his grandson said. The trip cost $5 each for the rest of the season. The famous flight occurred Jan. 1, 1914, and the St. Petersburg-Tampa Airboat Line carried 1,205 passengers before closing at the end of the tourist season on March 31.

Though it barely broke even it was the United States' first scheduled air carrier.

A.C. Pheil had moved to Florida in 1882, arriving in a covered wagon from Red Mill, Pa. His family cleared and farmed 900 acres in Citrus County, but moved to St. Petersburg and went into the lumber business after the freeze of 1890, said grandson Peter.