Frequent flyer miles can now be shared among friends and family on United.

• Up to five MileagePlus members can pool their loyalty points with United, which can be redeemed for flights and other products.
• JetBlue and Frontier already allow customers to pool frequent flyer miles.

Would you be willing to share your frequent flyer miles with your friends, according to a test of customer preferences?

On Thursday, United Airlines introduced a new feature for its MileagePlus loyalty program members, allowing them to combine their frequent flyer miles for trips on the airline.

Up to four family members or friends can join a "pool leader" in a joint account, and the leader must be at least 18 years old. However, pool members can be of any age, allowing families to utilize their children's miles piles towards tickets.

Customers can retain their own MileagePlus accounts and decide how much they want to contribute to the pool. The miles can be redeemed for flights and other products on United's site or app.

"The pool allows individuals to contribute any amount they choose, and once miles are added, they remain in the pool," stated Luc Bondar, the chief operating officer of United's MileagePlus loyalty program.

While United isn't the first airline to offer loyalty points pooling, it allows up to seven customers to pool frequent flyer miles. In contrast, allows up to eight people to pool miles. However, airlines generally allow customers to transfer miles to others, but that often comes with a fee.

"According to Henry Harteveldt, a travel analyst and founder of Atmosphere Research Group, the strategy for mileage pooling is to target less-frequent to moderately frequent travelers and encourage their family members to participate in the program. By pooling their award points together, family members can increase brand preference, similar to how toothpaste is shared among family members."