Air Canada offers Flight Pass (
https://fp.aircanada.com/wallet/serv...#/shopping/ALL) and Flight Pass for business, designed for multiple travelers.
United offers their PassPlus program (
https://www.united.com/web/en-US/con...s/default.aspx) which I am less familiar with.
SAS offers the Travel Punch Pass (
https://www.flysas.com/us-en/corpora...-travel-smart/) for multiple travelers, as well as an unlimited plan for a single traveler.