He awaits experiments to show that flapping pyramids and cones can stay aloft .

他期待拍动式金字塔和锥体能停留在空中这样的实验的出现。

As a result it can remain aloft for only a few days at a time .

最终它可以每次在空中保持几天。

Strong winds aloft and at the surface often accompany the formation of wave clouds , whether they develop in the troposphere or stratosphere .

在高处和在表面所刮起的强风形成往往伴随着云波的形成，不管在对流层还是在平流层。

The drone can stay aloft for 30 hours , plenty of time to collect data as hurricanes evolve .

无人机可以在空中停留30个小时之久，当飓风逐渐形成时，它可以长时间的收集数据。

An unmanned solar-powered drone has already stayed aloft for two weeks and some battery-powered electric trainer aircraft are also being developed .

一架无人驾驶的使用太阳能的飞机已经成功的在空中逗留了两周，一些用电池的飞机也在不断发展着。