GEORGETOWN, Texas – The search for the pilot who went missing while flying to transport a disabled dog is still active in the Gulf of Mexico.

Dr. Bill Kinsinger was last heard from on Jan. 4 as he left a small airport in Oklahoma City to fly to Georgetown, Texas.

Federal Aviation Administration spokesman Lynn Lunsford said the plane was last observed on radar 219 miles (352 kilometers) northwest of Cancun flying, at 15,000 feet (4,600 meters).

NORAD launched two F-16 fighters from a base in Houston and made contact with the plane, where fighters performed military maneuvers in an effort to gain the pilot's attention, but the pilot appeared to be unresponsive.

The North American Aerospace Defense Command said the pilot became unresponsive en route likely due to hypoxia, which cuts off oxygen to the body tissue. 

The Coast Guard aircraft will continue to search a broad area off the Yucatan Peninsula in Mexico.

The dog Dr. Kinsinger was rescuing was a part of the nonprofit group Pilots N Paws. On Friday, the dog Massaru made it to the rescue Dr. Kinsinger was scheduled to transport him to. The rescue said Massaru is resting up for diagnostic treatments.

Kinsinger serves on the Oklahoma Medical Board and lives in Edmond, Oklahoma. Kinsinger is an anesthesiologist.

Spectrum News will continue to follow this story as it develops.