I can tell you running a profitable aerial/terrestrial photography/videography business is a lot harder than most people think. Also, it sounds like you have a lot to learn about how airspace approval works and where you can/cannot fly. I have submitted over 30 waiver requests for everything from flying beyond line of sight, flying at night, flying at specific locations etc. with varying degrees of success. I literally typically have at least 10 waivers pending with the FAA at any given time.
Additionally you need to get a highlight reel together, start your business, get your EIN, register your domain for your website, create/build/buy your website, get some business cards, create a logo, trademark the logo, become better than your competition at photography, better than your competition at videography, keep up with the latest FAA regulations, pass your 107, become familiar with the waiver process, advertise to your target customers, etc. etc. etc. The list goes on.
I do think a business plan could be helpful, but maybe a bit overrated. If you are passionate enough about what you want to do, and start small you can be successful without one. I never wrote one myself, and have had no problem keeping solid bookings for up to 3-6 months out.
I do know that if you want to get a solid client base and survive every kid with a drone who wants to make money doing it you have to have better footage, better techniques, more efficient workflows, better SEO, better advertising, etc. than your competition, and after all of that; you still need to find a way to be profitable.
The biggest thing that I have found in my market that makes me stand out from my competition is that I have a more diverse service portfolio; I do everything from construction progression photography to interior/exterior photography, to interior/exterior video, to virtual tours, to 360 panoramas. I also do more than just real estate, I also specialize in fashion, models, portraits, and landscape. There are so many areas of photography and video that are out there, and if you diversify your service offerings you will start to get and keep clients in ways you never even imagined. Not to mention you will learn advanced photography and videography techniques that will make all of your footage stand out from your competition.