摘要: Free Flight is the buzzwords of the recent years. They usually apply to the users of the airspace system, the airline operators and the aircraft. It does not indicate that flying is for free now, but that the users should be as fr... 展开 Free Flight is the buzzwords of the recent years. They usually apply to the users of the airspace system, the airline operators and the aircraft. It does not indicate that flying is for free now, but that the users should be as free as possible in their operations. They can take-off from where they want, land where they want and take any route in between. And they should be able do do so whenever they want it. Now, it does not require a great deal of imagination to see that this will not always be possible for everyone. Some resources in the ATM system (especially runways) are so scarce that their use is restricted in some ways. In order to allow equal use by all users there will thus be a continuing need for a ground based ATM service. This paper tries to point out where the balance may be found. 收起