RE: jato bottles
Theere have been a number of rocket assist RC gliders on the market. Might try some of the model rocketry web sites, or the NAR (National Association of Rocketry) website. The RCM plan service, which might still be in existance, had one or two plans. Estes has had a couple planes. I have their Sweet Vee, which uses D or E size motors. Generally, they use rocket motors in D, E, F, or G sizes. Anything above G, you need to get high power certifications to even buy the motors. If you ever watch Mythbusters, they use up to M sized (Biggest available) motors to try to launch full sized cars. They apparently obtain them through someone certified through NAR or Tripoli. I think the first time they tried to verify a car loosing control, using AF JATO, or is it now RATO bottles, they couldn't obtain them. They did get a couple M sized model rocket motors, which apparently each have several times the thrust of the JATO.
I once had a plane manufacurered by the Aerotech company. A nice sleak looking boost glider powered by F or G composite motors. I had to stand about 50' away in order not to lose sight of it during the launch, it accelerated that quickly.
Most motors made for RC are plugged, that is, they do not use the ejection charge most motors have to eject the recovery parachute or streamer, so the end opposite the nozzle is plugged.
I think Flying Models plan service still carries a hybrid from the early 70s that teams a D sized motor with a .19 sized engine.
Some of the English publications had full sized plans in the mags for rocket boost gliders, including a Japanese "Okha", AKA Baka, and a V-1 Buzz Bomb. Might check with Traplet publishers. I think for a while Kalmbach Publishing was the agent for Aviation Model International which had the V-1 and Baka.
If you try one, lightness, low drag, and strength are vital. These motors usually hve a very high initial thrust followed by a drop-off to perhaps 1/3 to 1/2 the initial level, and often are burnt out in less than 6 seconds. I think I remember that the G sized can have an 18 pound thrust for almost a 1/2 second. That can tear weak wings and tail surfaces off real quick.
Generally, the motors in the RC boost gliders are not jettisoned for the flight. Ties in with the AMA guidelines for not dropping parts of the model.