I agree a portable DVD-player is choice, and you can bring it with you, esp. for those long airplane rides!

However, here's another idea:

Use your laptop! Although not the thinnest laptop available, (Dell Latitude CPx), it is plenty fast, with a big 15-inch screen, and with a Y-adapter for two headphones, and an inverter, you have a DVD player and a computer (I have StreetAtlas loaded).

All you have to do is get a mobile laptop car-mount installed and you're good to go!

:-) neil
1988 360TE AMG
1993 500E