The plane suddenly jolted shortly after takeover then felt like it was falling, said Stef Zamorano, who was flying to Las Vegas with her husband to celebrate his birthday.

A Southwest Airlines flight from Burbank made an emergency descent of 475 feet to avoid colliding with another aircraft before safely landing in Las Vegas on Friday.

Southwest Flight 1496 sharply descended nearly 500 feet, according to flight tracking websites, marking the second time in a week that a US commercial jet was forced to make abrupt flight maneuvers to avoid a potential mid-air collision.