They also have a list of residents who have already used the application in another city and have a registered credit card on file. (abovethecrowd.com)
The app links directly with your United MileagePlus account and you can store different credit cards on file for different purchases. (travelcodex.com)
To use ApplePay, you must be logged in to your iCloud account while using Safari and have a valid credit card on file. (chilitechnology.com)