録りたい方へ。
1. このような、ミニ端子付きステレオ・ケーブルを用意します。
http://ecx.images-amazon.co...
2. ケーブルの一方を座席の端子に、もう一方を録音機材に入れます。
3. 録音機材の入力レベルを調節します。

ほとんどの航空会社ではミニプラグが使えますが、キャセイパシフィック航空のように標準プラグを必要とする場合も稀にあります。また中国国際航空のように、オーディオのバランスが悪い場合もあります。

For those interested in recording on your own;
1. Grab one of these stereo cables.
http://ecx.images-amazon.co...
2. Plug one side into the connector of your seat, and the other to your recording device.
3. Adjust the input level of your device.

For most airlines, you need the cable with 1/8 inch (3.5 mm) connector. However, you might have to prepare an adapter such as 1/4 inch/6.35 mm for Cathay Pacific. Also, audio balance of several airlines such as Air China are very unstable, so you have to bear with that.

I'm a courier, delivering commercial products to all over the world, mostly from Japan.

Last, but not least, you don't want to put your request on the comments unless you buy me a return ticket.