While in the passive mode, ATTac-2000 does not bid in the airline auctions. In active mode, ATTac-2000 buys all currently unowned airline tickets needed for the current G*. In most cases, that means that it only bids for airline tickets during its first bidding opportunity in the active mode. However, in the face of drastically changing (hotel and entertainment ticket) prices, G* could change sufficiently to necessitate purchasing additional flights, instead of simply using the ones that have already been purchased.