I shoot a lot for real estate agents.... I also concentrate on high end properties (I shot a lot of little stuff to progress to where Im at). They usually have larger lots... so aerial is a benefit to them. I also use aerial as an ad on service.... most of my work/money is from shooting ground level. Not sure I could make aerial a business by itself.
Real estate agents are a funny breed.... if you are good and reasonable prices, it will eventually come together. They work so much with referrals... one agent will see another agents work... and find out where they got it done. And remember, there are a lot of Realtors... but only a small percentage are Sellers Agent... the Listing Agent. Because it also takes a lot of work on their part to get the listings.... and money (photography, marketings, etc.).
Go after the agents with five ore more listings. Do a few free shoots to show them the benefits.... especially if they have a lot of listings.... and always deliver more than they expect.
Below is one I shot last week.... again, I also did ground level interior and exterior.