1. A method for adaptive forecasting, comprising: receiving a request to forecast a number of tickets that will be sold for a future airline flight, wherein the future airline flight will depart: from a departure market, at a departure time, on a day of the week, and in a month in a quarter; retrieving a first permanent component, the first permanent component being a historical average number of tickets that were sold over a first time period for past airline flights that have departed from the departure market at the departure time; retrieving a first trend component, the first trend component being based on a first trend difference between the first permanent component and a first previous permanent component, the first previous permanent component being a historical average number of tickets that were sold over a second time period for past airline flights that have departed from the departure market at the departure time, wherein the end of the second time period occurred before the end of the first time period, wherein the first trend difference is positive if the first permanent component is greater than the first previous permanent component, and wherein the first trend difference is negative if the first permanent component is less than the first previous permanent component; retrieving a first seasonal component, the first seasonal component being based on a first seasonal difference between the first permanent component and a historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at the departure time, and that have departed on the day of the week, in the month, or in the quarter, wherein the first seasonal difference is negative if the first permanent component is greater than the historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at the departure time, and that have departed on the day of the week, in the month, or in the quarter, and wherein the first seasonal difference is positive if the first permanent component is less than the historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at the departure time, and that have departed on the day of the week, in the month, or in the quarter; determining, using a computer, a first forecast of the number of tickets that will be sold for the future airline flight, the first forecast being based on the first permanent component, the first trend component, and the first seasonal component; determining whether the first forecast is valid; and if the first forecast is not valid, then: retrieving a second permanent component, the second permanent component being a historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at either the departure time or one or more other departure times; retrieving a second trend component, the second trend component being based on a second trend difference between the second permanent component and a second previous permanent component, the second previous permanent component being a historical average number of tickets that were sold over the second time period for past airline flights that have departed from the departure market at either the departure time or the one or more other departure times, wherein the second trend difference is positive if the second permanent component is greater than the second previous permanent component, and wherein the second trend difference is negative if the second permanent component is less than the second previous permanent component; retrieving a second seasonal component, the second seasonal component being based on a second seasonal difference between the second permanent component and a historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at either the departure time or the one or more other departure times, and that have departed on the day of the week, in the month, or in the quarter; wherein the second seasonal difference is negative if the second permanent component is greater than the historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at either the departure time or the one or more other departure times, and that have departed on the day of the week, in the month, or in the quarter, and wherein the second seasonal difference is positive if the second permanent component is less than the historical average number of tickets that were sold over the first time period for past airline flights that have departed from the departure market at either the departure time or the one or more other departure times, and that have departed on the day of the week, in the month, or in the quarter; and determining, using a computer, a second forecast of the number of tickets that will be sold for the future airline flight, the second forecast being based on the second permanent component, the second trend component, and the second seasonal component.