You need permission from the land owner if you want to fly on private land. Local parks, school fields etc. often have local byelaws preventing "untethered flying models", which is primarily aimed at model aircraft flyers. The only thing you can do is to check with the respective local authority.

For models larger than typical Estes of Quest rockets, that will reach higher altitudes, then it would be advisable to fly these at an organised launch event. The organising club will have taken care of altitude restrictions and contacted the Civil Aviation Authority.