A Companion Certificate is a one‑time use certificate that lets you bring a plus one on an eligible round‑trip flight. You only need to pay the government taxes and fees, which start at $15.60. You can bring anyone you choose, so long as that person has a FRONTIER Miles number and it is added at the time of initial booking within the same ticket.
Companion Certificates are valid for one year from issuance. The expiration date is listed on your FRONTIER Miles Profile Page.