Question

1. A: Where can we hear this announcement?
B: We can here it in an airplane.

2. A: Where can we hear this announcement?
B: We can here it on an airplane.

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Q1: Do we have to use 'in' or 'on'?
Q2: Is the expression 'announce' (from athe pilot) correct?

Answer 1

In or on are both correct. If you are ONboard an airplane, you are IN the airplane. And "announcement" is correct.

Answer 2

B: We can here it in an airplane.

should be

B: We can <b>hear</b> it in an airplane.