California's Assembly Bill No. 723 doesn't explicitly call out changes to the sky, but it doesn't exclude it either.
Real estate brokers & sales staff working on their behalf would need to add a disclosure that the picture had been altered, and...
Unless substantial amounts of money are involved, hiring an IP lawyer would be a waste of money you'll never recover.
If someone uses your video without engaging in good-faith licensing negotiations, file a DMCA notice.
You are 100% not liable. As a matter of fact, you can sell your footage taken under a 44809 flight. Suppose this same scenario, but instead of stealing your imagery, they ask if they can buy it. You're 100% allowed to sell it.
While it may not be worth your time and money to file a civil action, you can file a DMCA takedown request anywhere your media is being used without permission. That's not difficult to do.