United tests shopping app with bonus miles on purchases

United Airlines has begun testing a new app that lets customers use their phones to make purchases at certain stores and earn extra United MileagePlus frequent-flier miles in the process.

So far, the MileagePlus X app is open only to a set of MileagePlus members invited to participate in a trial by United. The airline says the app will let customers use their iOS or Android smartphones for in-store purchases at retailers such as Lowe's, Sears, Gap and AMC Theaters.

Customers using the app can search nearby retailers and view the amount of miles they'll earn for making purchases with their app. United says users can also browse a catalog of all merchants or search for specific stores.

United explains how transactions work, saying:

"At check-out, customers enter the total dollar amount of their purchase via the app, creating a digital merchant gift card. The cashier then scans the barcode to complete the gift card purchase. Award miles will instantly appear in members' accounts in addition to any miles the customer may earn purchasing the digital gift card with a MileagePlus Credit Card from Chase."

"The new MileagePlus X app builds on the increasing popularity of mobile purchasing, enabling members to make in-store purchases and earn miles without having to pull out a credit card," Praveen Sharma, United's VP of loyalty, says in a statement.

United says access to the MileagePlus X app will be expanded to "all members and (will) offer more retailers soon." Additionally, United promises future improvements that will include new features, including the ability to redeem miles for in-store purchases.