Does Mobile Passport Control require Wi-Fi?

I want to use Mobile Passport for customs when I return to the U.S., do I need to connect to Wi-Fi to use it?

Yes, Mobile Passport requires a Wi-Fi connection to be fully functional. You will be able to enter passport information and answer the Customs and Border Protection questions while offline, but you will need Wi-Fi to submit them. After your plane lands you can use its Wi-Fi if available, or wait to use the airport's Wi-Fi so you can get your QR code receipt before you reach the customs area.