U.S. Coast Guard officials are trying to locate a small airplane they say went missing Wednesday while en route to Texas.

Officials say the plane took off from Oklahoma City Wednesday and was headed to Georgetown Municipal Airport, north of Austin, but diverted at some point and headed south.

Coast Guard officials say they lost contact with the pilot, Bill Kinsinger, after the plane flew past Freeport. The Naval Air Station Joint Reserve Base in New Orleans sent a plane into the Gulf to try and make contact with the pilot where they observed him slouched over in the cockpit.

Officials believe he was the only person aboard the privately owned Cirrus, and the pilot was unresponsive likely due to hypoxia.

Multiple pet rescue organizations tell KHOU 11 News Kinsinger is a volunteer pilot who flew several missions for different pet organizations.

Gia Fowler works with a rescue group out of Las Vegas. Kinsinger was heading to Texas to pick up a dog for them when air traffic control lost contact with him.

"Every hour he spent flying dogs is an hour he wasn't with his family," Fowler said. "We're devastated."

A search is now underway for where the aircraft likely went down. The Coast Guard says that search will go on throughout the night.

Wade Roberts is a local pilot who also flies rescue missions for Pilots N Paws. He teamed up with Kinsinger often.

"He was one of those who never turned down a mission or request," Roberts said.

A Facebook page titled "Saving Masaru the senior husky" states the pilot was on a mission to transport an elderly dog, but the animal was not on the plane when it went missing.