Additional relief for Grand Canyon tour operators using quiet-technology aircraft–as defined in FAR Part 93–has been proposed. Tour operators flying quiet-technology aircraft in the Dragon and Zuni Point corridors would be relieved from having such flights count against their annual allocations in the first quarter of next year and possibly beyond. This incentive is one of several adopted over the last decade to encourage wider use of quiet-technology aircraft as a long-term solution for reducing air tour noise. Comments on the proposal are due December 10.