Aircraft engines are optimised for level flight at cruising speed in the stratosphere.

飞机引擎被调校以适应在平流层以巡航速度水平飞行。

One of the things I love about flying these helium balloons is they have the capability for real expedition level flights.

我喜欢飞这些氦气球的原因之一是它们是真正的探险级别的飞行。

Paul focused on the glowing globe within the attitude curve, fought his craft back to level flight.

保罗将注意力集中在姿态曲线内的发光球体上，将他的飞行器打回水平飞行。

It left them in a position where they were just hanging on trying to hold the airplane at a reasonable level flight.

这导致他们只能尽力让飞机在一个合理的水平飞行。

The next step is to get the paramedics to Tony Stark level flight skills in the jet suit so that they can begin providing rapid response to emergencies.

下一步是让护理人员掌握托尼·斯塔克级别的喷气式飞机飞行技能，以便他们能够开始对紧急情况做出快速反应。

PID controllers are everywhere, from the cruise control in your car, to drones that automatically adjust their rotor speeds to maintain level flight, as well as more exotic robots, like this one that balances on a ball to move around.

PID 控制器无处不在，从汽车的巡航控制，到自动调整旋翼速度以保持水平飞行的无人机，以及更奇特的机器人，比如这个靠球平衡移动的机器人。