When I watch movies on planes I end up holding the phone for 2 hours or having the tray-table down and using the Mini stand for iPhone & iPod Touch by MakiYoshida (http://www.thingiverse.com/thing:2205). There are worse fates, but having the tray table up gives me more freedom of movement for my long legs. I wanted an iPhone hook for the tray table in the up position, so I designed and built this.
It clips over the tray table when up, and props the screen up when placed on the tray table so you can keep watching while you eat your snack (with the tray-table down).
This is similar to the iPhone Universal Stand by juniortan (http://www.thingiverse.com/thing:2426) but more for a specific function.