Need to 'borrow' miles from your kid to get that free flight? A big airline will let you do that

What if you don't have enough airline miles for that free flight, but a family member does? United Airlines is now letting families and friends pool and share their frequent-flyer points. The airline said Thursday that a “pool leader” can pick up to four other people to set up a shared account in its MileagePlus program. JetBlue, Spirit and Frontier also offer pooling, with the rules varying a bit from one airline to another. Frequent-flyer programs remain popular despite complaints that the value of miles and points decline over time because airlines raise the requirements for redeeming them for flights.