Recreational / Hobbyist UAS pilot reported flying in controlled airspace without authorization.

Narrative

I was shooting a video and taking pictures of my son's workplace at a warehouse. I shot some video and took pictures inside the warehouse; and my son asked me if i could shoot a few of the outside of his building. My battery level was low; but i did a quick fly around the warehouse at an altitude of around 50'. The battery got low enough that the drone decided to fly back to the home point before the battery ran out. I had forgot to reset the return to home altitude to a low number; it was set at 100m. The drone rose to 100m and proceeded back to home. The horizontal distance was probably around 200-300 feet. I realized I was about 5-10 miles from IAH airport and it dawned on me that I was probably in Class B airspace. I had not intended to go above the power lines around the building; but the auto return to home took the drone up to 100m(328 feet); so I realized I had messed up and made a mistake. We were that close to the airport and no planes were noticed near us.I will plan better in the future and check my drone settings.