A drone is the way to do it, forget abut rockets or balloons.
You can climb way more than 1,500 m with a hacked M3, but the Fly app stops counting at 3,150 m. You still have juice to get to 4,000 m or more, but since you don't know the alt...
Rules, safety and bureaucracy are three different and independent parameters.
While Vic explains the papers you must fill to comply with the rules in the US, he doesn't say anything about temperature, wind or battery, which are the things that...