This isn't going well.

Less than 24 hours after making headlines for giving members the ability to pool miles with friends and family for free – a first among the biggest U.S. carriers – United Airlines has pulled the plug. Temporarily, it says.

After being available immediately online after launching Thursday afternoon, that feature disappeared from United's website and smartphone app by Friday. A dedicated landing page merely said: “We experienced some unexpected technology issues and look forward to bringing back our new miles pooling feature soon.”

Reached for comment, a United spokesperson declined to share more details on what happened or an estimate for when it would come back online – adding only that “we hope to have the feature back soon.”

The victory lap for the Chicago-based airline was short-lived. In theory, it would have been groundbreaking.

Up to five travelers can share and redeem miles for free from a joint account – and they don't have to be in the same household … or even related.

One designated pool leader can redeem miles for the entire group or authorize other members of the pool to do so. There's only one major limitation: Only redemptions on United and United Express are allowed when redeeming pooled miles – not United's many Star Alliance partner airlines like Lufthansa, SWISS, All Nippon Airways (ANA), and others.

Each member can decide individually how many miles to kick in to share with the group: You don't have to share your entire balance of miles just because you join a pool. While pool leaders must be at least 18, there's no age requirement for other members to contribute miles.
 

united miles pooling 

If it works, it's a major change that will allow friends and family members who may only have a few thousand United miles to share them without paying a steep price. Like other U.S. airlines, United charges hefty fees to transfer miles directly between accounts: $15 per 1,000 miles, plus a $30 processing fee. That means sharing just 10,000 United miles would cost $180.

Now, United members can simply create a pool and combine those miles for free. While JetBlue allows members to pool points along with several foreign airlines, the larger U.S. airlines like American, Delta, and Southwest (with far bigger loyalty programs) have never done it.

You can only combine MileagePlus miles – the ones you redeem to book an award ticket. Travelers can't pool together Premier Qualifying Points, Premier Qualifying Flights, or PlusPoints – the building blocks of earning United status – to help the pool leader earn status. Travelers also can't pool TravelBank credits together.

But this new option to pool points will be a major plus for traveling families who want to be on the same reservation. Gone are the days when your child's or partner's miles are stuck in limbo in their account: Now, the family can use all of those earned points and book together. Or a child with just a few thousand miles that may never get used can kick them into a pool to finally get used.
 

United check in 

United members can only participate in one pool at a time. If you leave one pool, you'll have a 90-day waiting period before being able to join another … and, more importantly, you'll forfeit any miles you shared with your previous pool.

Several major international airlines including British Airways, Emirates, and others have long allowed members to pool their points for years. And major U.S. credit card companies like Chase and Capital One allow cardholders to transfer points to others, though Chase restricts those transfers between members of the same household.

To the north, Air Canada's Aeroplan frequent flyer program joined with a Family Sharing program … but that has been shut down for more than six months due to widespread fraud.

Those concerns are part of the reason why it hasn't spread to the bigger U.S., whose loyalty programs and credit card relationships are massive financial engines. Those airlines also love charging members to share their miles: Delta, for example, charges 1 cent per mile plus a $30 fee – $130 to transfer 10,000 SkyMiles to a family member.

United appears to be trying to get ahead of the prospect of fraud by limiting pool redemptions to only United and its regional partners. The airline has also recently implemented a one-time account verification process via cell phone for MileagePlus members logging in.

But the airline industry is cutthroat, and airlines hate seeing a competitor gain an edge. If United's feature comes back and is as popular as we suspect – and immune from fraud – it may only be a matter of time until the likes of American and Delta join in the pool party, too.
 
Thrifty Traveler editor Kyle Potter contributed to this story