Flanked by Speaker Thomas P. (Tip) O'Neil Jr. and Majority Leader Jim Wright (D-Tex.) the chairman of a House Public Works subcommittee on transportation yesterday announced year-long hearings that he said would result in legislation providing a comprehensive policy on highway and mass-transit funding.

Rep. James J. Howard (D-N.J.) also announced a proposal of his own, which would result in a 3-cent-a-gallon increase in the current 4-cent-a-gallon gas tax that funds the Highway Trust Fund. He also would set up a separate mass-transit trust fund to be financed by diverting 2 per cent of current corporate profits, amounting to about $2 billion a year, to a new mass-transit trust fund.

But while both Wright and O'Neill endorsed a separate trust fund for mass transit, neither would endorse the rest of Howard's plan.

"No way" . . . said O'Neill of Howard's proposal for a 3-cent-a-gallon increase in the gas tax. Wright said he did not necessarily endorse Howard's funding mechanism.

President Carter has called for an increase in the gas tax of 5 cents a gallon up to a maximum of 50 cents a gallon if gas consumption isn't reduced.

Howard said he was against Carter's gas tax proposal because it was "regressive" and would not conserve energy anyway. He said gas would cut down on consumption0 a gallon before Americans would cut down on consumption.

But he urged that instead of Carter's gas tax plan, the ways and Means Committee vote a 3-cent-a-gallon increase that would raise an additional $3 billion to be used solely for bridge repair, highway maintenance and highway safety programs.

He said there was currently not enough money in the Highway Trust Fund to repair "105,000 unsafe" bridges and deteriorating roads. As of last month. Howard said, here was $9.1 billion in the Highway Trust Fund, but $24 billion worth of projects to fund.