Lyft customers can once again earn miles toward their next flight.The ridesharing company on Wednesday said it's partnering with United Airlines to offer MileagePlus points to riders who link their accounts, months after it ended an eight-year partnership with Delta Airlines.Once linked, riders can earn one mile for every dollar spent on Standard Priority Pickup and XL rides and two miles for every dollar booked on business profiles. Extra Comfort, Lyft Black, Black SUV and regular airport rides will earn t ...