Do the films available through the Library include Public Performance Rights?
For library resources, any of the streaming videos in our AVON database (Academic Video Online) include PPR as long as admission is not charged. Here is the link to the database: https://guides.lib.rpi.edu/avon
Worth noting is some Netflix documentaries allow for one-time educational screenings, details here: https://help.netflix.com/en/node/57695
Otherwise, the way to obtain PPR is to contact the copyright holder or distributor. For major feature films there are licensing services available like Swank: http://www.swank.com/