What about a much "quieter" option... a "weather" balloon or a kite controlled by a kite line or similar? For a kite you'd need a bit (or more) of wind but not for the weather balloon... just some helium. Landing a kite could also be a bit tricky regards possible damage to the camera... probably not so much so with a balloon.
In Falconry, kites and balloons (weather type, 5' or 6' ones) have been used for many years - by some falconers - for training falcons to gain height when the falcon is intended for use in hunting game birds like grouse, pheasants, partridge and wildfowl such as ducks. Anyone that has been to "The Falcony Fair" will probably seen them used in a part of the demonstrations.
If going above a certain height a licence is required from the air authority - can't remember their exact title.... sorry