HOUSTON, Jan. 4 (Xinhua) -- U.S. Coast Guard officials Thursday are still looking for a small airplane that went missing a day ago en route to Texas, the United States.

After taking off from Oklahoma City, Oklahoma Wednesday, the plane was headed to Georgetown, Texas, but diverted at some point and headed south, officials said.

They believed the pilot, Bill Kinsinger, was the only person aboard the privately owned Cirrus aircraft, and was unresponsive likely due to hypoxia.

Coast Guard officials said they lost contact with the pilot after the plane flew past Freeport, an area close to the Gulf of Mexico.

The Naval Air Station Joint Reserve Base in New Orleans sent a plane into the Gulf to try to make contact with the pilot, who they observed slouched over in the cockpit.

According to reports, Gia Fowler, who works with a rescue group, said Kinsinger was heading to Texas to pick up a dog for them when air traffic control lost contact with him.

Multiple pet rescue organizations told local TV station that Kinsinger is a volunteer pilot who flew several missions for different pet organizations.