OTTAWA, Ont. -- Some of the most vocal critics of the Harper government's plan to buy F-35 jets were on parade today on Parliament Hill.

Winslow Wheeler, a defence procurement expert who worked for U.S. General Accounting Office, says Canada would be foolish to buy the stealth fighters before 2019.

That's when the Lockheed Martin-manufactured fighter exits its development phase.

Wheeler spoke before a group of New Democrat MPs in what the opposition party says is an extension of public accounts committee hearings.

The all-party House of Commons committee held hearings last spring after the auditor general slammed the planned purchase of 65 multi-role fighters.

New Democrat Malcolm Allen says the party organized the hearing, during Parliament's summer recess, in order to get the testimony of experts on-the-record.