The airline ticket Q surcharge itself is generally used by airlines as a way to charge customers for what they say are miscellaneous additional operating costs. Airlines also use ticket surcharges because they're easy to add to or remove from fares. A flight from New York to London, for example, may list a base fare plus surcharges on peak travel days but few surcharges on non-peak days. Plus, airlines add ticket surcharges simply to enhance revenues.
According to the Airline Tariff Publishing Company, the Q surcharge is used by airlines to support 16 different fees. In addition to peak travel times, a Q surcharge may be added to an airline ticket to cover more expensive fuel. Q surcharges on tickets are also imposed by airlines when they change the aircraft used on a particular flight. Passengers flying in an airliner that's more expensive for an airline to operate, for instance, may see Q surcharges imposed.