The Senate Appropriations Committee last night approved a measure banning smoking on commercial airline flights lasting two hours or less.

Voting 17 to 12, the committee ratified a subcommittee decision barring in-flight smoking for three years as part of a bill authorizing $11.2 billion in transportation spending.

The vote adds significant impetus to this year's fight in Congress to bar cigarette smoking aboard commercial flights, but the issue is likely to face more difficult hurdles in the full Senate. Smoking of cigars and pipes is already forbidden on airliners.

As part of its own version of the transportation appropriations bill, the House has backed a similar ban on smoking on short flights, although the measure it passed in July would provide a permanent, rather than three-year, ban.

Whether the Senate bill would go to a separate floor vote or be included in an omnibus spending bill later this year is unclear. Opponents of the ban would have a better chance of defeating it if it is part of a separate spending bill than of a catch-all bill covering spending for most of the government.

Pushing the prohibition through the full Senate is more difficult than House passage because lawmakers from tobacco-growing states have proportionally more power in the Senate.

It is estimated that a ban on smoking aboard flights of two hours or less would affect about 80 percent of domestic commercial flights. Earlier this week, California legislators banned smoking on flights originating and ending in that state, effective Jan. 1.

In approving the Senate committee measure, a majority on the panel repelled an attempt by Sen. Ernest F. Hollings (D-S.C.) to strike it from the transportation subcommittee's bill because it represented an attempt to legislate government policy on a spending bill.

"This is the most blatant kind of legislating on an appropriations bill," Hollings said. "It's a poor way to legislate."

Sen. James R. Sasser (D-Tenn.) argued that the Senate should not take such a step without extensive public hearings. "We just don't have the information to make a judgment of this magnitude," he said.

But Sen. Frank R. Lautenberg (D-N.J.), chairman of the transportation subcommittee, said there is ample scientific evidence to justify the ban. Citing studies by the U.S. surgeon general and the National Academy of Sciences, Lautenberg said, "The fact is it's dangerous . . . to be a passive smoker."

The committee vote came as the House authorized $28.5 billion over five years to fund improvements for U.S. airports and the air traffic control system. The House approved the measure, 396 to 0.

The bill authorizes expenditures of about $4.9 billion in the fiscal year that began yesterday, $1.2 billion more than spent last year.

The House narrowly defeated an amendment that would have removed the aviation trust fund from the federal budget, which would have protected the fund financed by a tax on airline tickets from automatic deficit-reduction efforts.