Uncontrolled airspace is designated Class F, while controlled airspace below 5,490m above sea level and not in the vicinity of an airport is Class E.

无交通管制的空域被定为等级 F，而低于海拔5490米、不在机场附近的管制空域是等级 E。

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On a clear day, a pilot in controlled airspace can choose a VFR or IFR flight plan, and the FAA regulations were devised in a way which accommodates both VFR and IFR operations in the same airspace.

在晴天，在管制空域内的飞行员可以选择目视飞行规则或者仪表飞行规则的飞行计划，而且联邦航空局的条例是以这样一种方式设计的：在同一空域同时适用目视飞行规则和仪表飞行规则的操作。

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In certain areas, mainly near airports, controlled airspace extends down to 215m above the ground, and, in the immediate vicinity of an airport, all the way down to the surface.

在某些区域（主要是机场附近），受管制的空域一直延伸到距地面215米之上，而且在紧邻机场的区域，控制区域一直延伸到地表。

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Central European time from Manching Air Base and climbed to a ceiling of 54, 000 feet within military controlled airspace, far above and at a safe distance from civilian air traffic.

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But for now its airspace remains tightly controlled by the armed forces, and owners of private planes have to fly through a smog of bureaucracy.

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