They also said the FCC rules on self-certification, and the absence of a national database of participants, made it hard to keep ineligible people from signing up.
"There's never been any proof that self-certification ever resulted in a problem in an aircraft, " said John Goglia, a former member of the National Transportation Safety Board, the nation's top aviation investigation agency.
The Federal Council stopped short of requiring a certification, but noted that a credibly designed self-declaration can be a strong indicator of tax-compliant behavior.