The story says the pilot say the smoke trail. That would indicate to me the rocket was still under power. Amateur rockets will easily go this high. 8 miles from the airport is a decent distance and would be adequate for most rockets.
Something doesn’t add up though. We are supposed to believe a commercial jet was at 5000 feet of altitude 8 miles from the runway. The plane had taken off and should have been gaining altitude.
Do any pilots on here know what altitude the jet should have been at?
IMO it seems more likely a govt attempt to squash amateur rockets than anything else. A ground launched missile would have went for the engines and not the cockpit.
The jet would have been talking to departure control and maintaining an assigned altitude like 6,000 feet and a specific speed and direction. A airliner can climb steeply if it wants to but holds off until it’s far from the airport traffic area.
I don't know about Houston, but some airports (like John Wayne in OC) have "noise-abatement" procedures, where they have to climb sharply and level off quick at a lower altitude, drop the power and get out of town before they continue up to whatever altitude they are headed for.
What they go for and what they actually manage are two different things, Especially if they've burned out or the seeker loses lock for some reason.