Steam pressure to push the water through the grounds quickly, yes.

But if you want simple and low-volume french-press coffee-tea, then you can try Bodum's press mugs. Super simple and you don't have to worry about the mess until you're awake and potentially at your destination if you leave the house with it.

http://www.seriouseats.com/2010/06/gadgets-bodum-french-press-travel-mug.html

Stainless variant:
http://www.amazon.com/Bodum-Stainless-16-Ounce-Vacuum-Silicone/dp/B0026L7DWE/ref=dp_cp_ob_k_title_0