Passengers aboard a Southwest Airline jet that took a dramatic plunge to avoid an oncoming aircraft were told by the pilot that they nearly struck another plane before landing safely in Las Vegas. The Boeing 737 jet dropped hundreds of feet in a little over 30 seconds during a flight on Friday, according to a flight tracking website.

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.