Bill. Good luck with your new venture. I started 4 years ago with the same idea...offering drone photography to real estate agents. What I quickly learned was 1) Many agents are loyal to their existing photographers who provide interior/exterior and drone photography. 2) Offering only drone photography to agents, or real estate photographers, will severely limit your opportunities. 3) Some real estate agents are frugal and prefer to use their telephone to take photos...call these agents... your target market! I started by showing up at Open Houses on Sundays and offering to take (free) interior/exterior photos and post them on my Real Estate Photography FB page. 100% said yes....just don't get in the way. In addition to your drone, purchase a used DSLR Crop Frame camera and tripod and watch all of the Real Estate Photography videos on Youtube. BTW, I deliver all photos to the realtor via dropbox link sized to approx 2mb through Lightroom CC.
Best wishes in your new business. I have had a blast.
Sowder Real Estate Photography & Drone Aerials