on the plane or in the plane

[Teo]

1. I flew to Hong Kong __ a plane which was very big.

2. I've never been up __ a plane.

3. I'm taking this magazine to read __ the plane .

Please use in or on to fill in the above blanks.
What's the difference in meaning between on a/the plane and in a/the plane?

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Thank you very much for your reply.

[Alan]

'On' for commercial airliners.

'In' for private planes/light aircraft.

'Be up in a plane' = fixed expression