Originally Posted by
seawolf
Paper application for NEXUS indicate you don't need passport. However not sure if you can use NEXUS Air if applied without passport.
Yes, you can. I did it in August 2017, EWR-YVR, with no passport linked to my NEXUS account. I did carry my US birth certificate and DL as backup proof of citizenship and photo ID, but was never asked for them. If you fly United internationally from Newark without a passport, you must visit United's "Additional Services" desk to have your travel document verified and boarding pass issued. Allow a few extra minutes for this. Passport holders can check-in using the self-serve kiosks.