It's not what you're thinking.
3 seconds sound clip from the The High and the Mighty (1954) movie soundboard.
You can hear this line at 00:32:41 in the DVD version of the movie.
Quote context
[...]
- I'm glad you decided to try a flight with us.
- Aren't there two exits to this plane? One up forward where you and the rest of the crew leave?
- Yes. (2)
- Could I leave the plane that way? With you and the crew? Please, it's very important to me.
- It's not what you're thinking.
[...]