] By the afternoon, one plane to Denver had been delayed
] several hours. United personnel kept asking for
] volunteers to give up their seats and take another
] flight. They weren't getting many takers. Finally, a
] United spokeswoman got on the PA and said this, "Folks.
] As you can see, there are a lot of soldiers in the
] waiting area. They only have 14 days of leave and we're
] trying to get them where they need to go without spending
] any more time in an airport then they have to. We sold
] them all tickets, knowing we would oversell the flight.
] If we can, we want to get them all on this flight. We
] want all the soldiers to know that we respect what you're
] doing, we are here for you and we love you."
]
] At that, the entire terminal of cranky, tired,
] travel-weary people, a cross-section of America, broke
] into sustained and heart-felt applause.
]
] And, yes, people lined up to take the later flight and
] all the soldiers went to Denver on that flight.

Not an urban legend. Verified. True. :)

Snopes: True support of the troops (*not* an urban legend)