The chairman of the MTA told an Assembly committee yesterday that the main obstacle to a deal needed for the Jets to build a stadium at West 30th Street was the team’s insistence that it should have to pay only $37 million for air rights.

The chairman, Peter Kalikow, and the Metropolitan Transportation Authority’s executive director, Katherine Lapp, answered questions from Assembly members on the authority’s plans to enter into binding arbitration with the Jets over the sale of the air rights at the Hudson Rail Yards. Presided over by a Westchester Democrat, Richard Brodsky, the hearings focused on the MTA’s decision to sell the Jets the air rights to the 13-acre site – without attempting to attract other bidders – at a time when the agency is projecting a $586 million shortfall for fiscal 2006 and is counting on the sale of assets, including the development rights at the West Side site, to cover the gap.

The Jets’ appraisal puts the value of the air rights at $352 million, but when the cost of building a deck over the rail yards is factored in, they maintain the price should be $37 million. The team has offered $100 million to the MTA for the air rights. The MTA values the air rights at $923 million, but the authority is willing to accept $300 million, or about one-third, because the Jets would use one-third of the site’s air rights.

A major sticking point in the negotiations, Mr. Kalikow said yesterday, is not the discrepancy in the appraisals but the Jets’ attempt to pay only the value of the site without the deck. After all, he said, proposed contributions to the project of $300 million each from the city and the state are earmarked to build the deck over the rail yards and a retractable dome over the stadium.

“This is the one nut we cannot crack. The Jets are getting money to build the platform, and therefore the MTA should not have to give them a credit for the value of the land minus the platform,” Mr. Kalikow testified.

The matter is to be submitted to binding arbitration by a former Senate majority leader, George Mitchell, who is now board chairman of the Disney Corp. The Jets’ position is that their deduction of $315 million – they call it a credit – is appropriate because building atop a rail yard creates extra construction costs that need to be considered. When asked if restoring the $315 million to the Jets’ offer it would close the deal, Mr. Kalikow said: “It would certainly move the ball down the field a great distance.”

The MTA chairman also described the MTA’s appraised value of $135 a square foot for the air rights as “slightly aggressive,” saying a more reasonable price was in the $100-a-square-foot range. Another critique of the plan raised in the hearing was the decision to allow the Jets to buy only one-third of the air rights, leaving the MTA with the remaining two-thirds to sell separately.

“I don’t think it is that great a risk, and in my experience, the Jets are offering us money up front and it is better to have a bird in the hand,” Mr. Kalikow testified.

The Regional Plan Association issued a statement on the issue yesterday that criticized the state-run entity.

“With circuitous reasoning,” the nonprofit think tank said, “the MTA assumes that it will retain the right to sell two-thirds of the air rights after the stadium is built, even though no transfer rights have yet been established and there are no sites to where the rights could be transferred. Building the stadium effectively takes away the only place where the development rights could realistically be used – on the Hudson Yards themselves.”

Mr. Kalikow also became the target of a letter-writing campaign yesterday. A West Side Council member, Christine Quinn, and other elected officials urged residents to write the MTA chairman to demand that any sale of the air rights follow competitive bidding and not shortchange subway and bus riders in a sweetheart deal with the Jets.