Allegiant Air spokeswoman Hilarie Grey said more than a dozen people had accepted the airline's offer, which was posted on Facebook, by midday Tuesday. Both airlines said they were working with local hotels to provide lodging help for family members arriving from out of town.
Allegiant is headquartered in Las Vegas. Southwest operates about 218 departing flights a day there, making Las Vegas the third-biggest operation in the Dallas-based airline's network. At least 59 people were killed and more than 500 injured when a gunman in a nearby hotel opened fire on the crowd at a country music festival Sunday night.
Grey said about 30 people fleeing the shooting climbed over fences at McCarran International Airport, run across active runways and took cover in an Allegiant Air maintenance facility for several hours. Mechanics on the overnight shift helped them charge phones and contact friends and family, she said.