I was chasing a boat over the ocean, the Air keeps up with no issue in sport mode. Tricky part was I was standing on a hill above the water and so my height readings on the teeny iphone display were all negative numbers. I didnt exactly know what was true sea level, plus against the dark background of water it was almost impossible to see until I popped it up into the sky again. Only after I watched the video on the computer did I realize I was literally inches away from smacking the boat windshield, and/or injuring my friend. Stupid noob error even though I’ve been flying for 5 years. All turned out fine but new learning for me on knowing the true floor when flying below your home point.