Tory critic Frank Klees, who sits on the committee, said he'll put forward a motion to haul in the premier to testify.
The public needs to hear from McGuinty about Ornge, which is currently under a criminal probe for financial irregularities, he said.
McGuinty has "refused" to answer most questions about Ornge over the last few months, Klees added.
"I think what's owed to the people of this province is a response from the premier, who ultimately is responsible for the decisions that are made in this government," he told McGuinty in the legislature.
The premier at first punted Klees' questions to government house leader John Milloy, then finally rose to respond. But McGuinty wouldn't say whether he would be willing to appear before the committee.
"I would suggest that a confused public might pay attention to objective, dispassionate, arm's-length, non-partisan, reliable officials in this matter," McGuinty told the legislature.
"That's why we had the auditor take a look at this. I think it's important that we rely on his observations and his recommendations."
The public should also wait for the results of a police investigation of financial irregularities at Ornge, McGuinty added.
Ontario's auditor general has criticized the Liberals for giving Ornge $730 million over five years with virtually no oversight of how the money was spent.
The air ambulance service has been mired in controversy for months over high salaries, questionable business deals and allegations that public dollars may have been used for personal gain.
The governing Liberals keep deflecting questions on Ornge by saying it's being dealt with by the committee, Klees said.
"I'm saying, fine, I'm happy to deal with this in committee, but I believe the people of Ontario deserve to hear from their premier," he said.
The Liberals reached a deal with the Progressive Conservatives and New Democrats late Wednesday to add another six hearing days on Ornge throughout the summer in exchange for an agreement to pass the minority government's budget bill by the end of June.
"We wanted to extend the time that the public accounts committee met on Ornge and we achieved six more days," said Tory house leader Jim Wilson.
"It's six more days to have some transparency on a very serious issue."
Klees said he wants to know what McGuinty knew about the performance agreement that created Ornge, and why the Liberals approved it over the concerns of senior civil servants.
He also wants to know why Ornge's ousted CEO Chris Mazza was entrusted with an organization that receives $150 million a year from the province when he wasn't qualified or experienced enough to run it, according to the testimony of one former Ornge executive.
"This has now reached the doorstep of the premier's office," Klees said.
"Hopefully we don't have to issue a speaker warrant to the premier, who puts him in the same class as Dr. Mazza."
The committee has spent weeks trying to haul in Mazza — a central figure in the scandal that's engulfed the air ambulance service — for questioning.
Speaker Dave Levac signed off on a rare speaker's warrant to compel Mazza to appear, but the committee was told that he couldn't testify.
Mazza, who took medical leave from Ornge last December, was declared unfit to testify by two psychiatrists, according to his lawyer.
But it looks as though Mazza may appear before the committee on July 18, said NDP health critic France Gelinas.
Getting Mazza before the committee is more important than forcing the premier to appear, Gelinas said.
"I have no problem questioning the premier," she said. "Is he at the top of my list right now? Absolutely not. I have my eyes set on Dr. Mazza."