Mercer County, N.J., executive Brian Hughes has announced plans to release tail numbers of aircraft that operate at Trenton Mercer Airport between midnight and 6 a.m., a voluntary curfew period, to anyone who calls the airport, gives the time of the operation and asks for the tail number. Aircraft operating during curfew hours are not violating any laws and cannot be fined. Corporate operators and the National Guard oppose the action for security and competitive reasons. Every quarter the airport will post on its Web site a list of tail numbers for aircraft that operated during voluntary curfew hours, but won’t include the times.