This is the second time this type of event has been reported by a commercial pilot in this area. The latest occurred on Friday:
A pilot reported to the Federal Aviation Administration that at about 8:15 p.m. Friday, an object passed within 150 feet beneath the aircraft, sheriff’s officials said.
The aircraft was near the southern edge of the county, flying at about 13,000 feet, officials said.
“The pilot, from what we understand, was former military. He was able to get the coordinates down real quick,” said Cpl. Hugh Bishop with the Liberty County Sheriff’s Department.
13,000 feet is definitely an altitude within reach of a high-powered model rocket but flights to that kind of altitude are far from common. If there’s someone in the area with the hardware and experience to build that kind of rocket investigators should be able to locate and interview them relatively quickly.
John Little has been breaking and explaining critical national security, intelligence, and technology stories 
High Powered Model Rockets are supposed to be launched with FAA awareness and permission. The kind of model rocket you can buy in the hobby store generally won’t go even a mile high.