1(of an aircraft or rocket) to take off; to lift off
2(fig.) (of an enterprise etc) to start to develop rapidly
Examples
nǐ你de的fēi jī飞机shén me什么shí hou时候qǐ fēi起飞ne呢？
你的飞机什么时候起飞呢？
When does your plane depart?
你的飞机什么时候起飞？
What time does your plane leave?
我们很快就要起飞了。
We will take off in a few minutes.