Officials are searching after a 16-year-old girl from Colorado seemingly vanished while flying from Phoenix to Denver on Monday.

After traveling to Arizona alone to visit her father, Whitney Lulloff’s flight home left Phoenix at 10:30 a.m. and landed in Denver at 12:30 p.m.

However, her dad Kris Lulloff said she never texted him to let him know she landed.

“She always texts me when she lands,” Kris Lulloff told Fox 21 News. “Her flight landed in Denver, and we didn’t hear from her. No texts, nothing.”

Kris Lulloff said the Phoenix Police Department confirmed that Whitney got on the plane in Phoenix.

Whitney’s stepfather was waiting at Denver International Airport to pick her up, but she never came out or contacted him.

Whitney is about 5-foot-7, 140 pounds with an athletic build, straight blonde hair and green eyes. She was last seen wearing ripped black jeans, black high top shoes and a light grey sweater.

The Denver Police Department said investigators do not yet have reason to believe foul play was involved in Whitney’s disappearance.

Officials are asking for witnesses who were on American Airlines flight 2511 with Whitney. Particularly, officials want to know if she was seen talking to or meeting anyone during or after the flight.

Kris Lulloff, a former law enforcement officer, told Fox 21 News that time is of the essence to find his daughter.

“I’m pleading for some sort of hope to know Whitney is OK,” he said.

Anyone with information is asked to call Metro Denver Crime Stoppers at 720-913-7867. Tipsters can be anonymous and are eligible for a $2,000 award.