Even stupider than what was it, “Airport 75”(?) where a fully pressurized 747 sank into the ocean (without tearing apart or landing, without crumpling once submerged)? Never underestimate the ability of Hollywood to misunderstand how reality works.
There was a proposal many years ago, IIRC, to put a small rocket engine into the back end of a 747(?) and use that to boost it to a much higher altitude (60,000 ft? 75,000 ft?) where it would drop a small rocket; much like the underwing launch of the Pegasus - but the extra altitude and thinner air would give it more of a head-start.
As others point out, the typical passenger jet is not designed to work above about 50,000ft. The modifications needed would essentially make a new aircraft. Much bigger control surfaces, if not a attitude rocket system for control; possibly to be effective at thinner altitudes, the wing airfoil shape and even wing size might need updating. The current pressurization equipment would be inadequate due to thinner incoming air - would need bigger stronger pups; I don’t know if the current airliner designs tolerate a certain leakage and let the pumps keep up pressure, but if the seals are good, then presumably a short stint in the much tinner air would be doable.
Like the 747 example I cite, the problem too is speed. Unless we’re talking Concorde (in which case, build from scratch, use a B2 or something) the airframe and airfoil, nose shape, hull and wing strength, etc. are not designed for supersonic. Depending how you attach the rocket, the attach points have to be able to handle the stress of forcing the aircraft through the air until it gets to the thin air, much as the jet engine pylons do.
The iconic SR71 had a number of adaptions for travelling at 3,000mph - to allow the aircraft not to melt from friction, it was mostly corrugated titanium - corrugated to allow for expansion with the friction heat from Mach 5 at 80,000 feet.