Yes, it is physically possible to visit both Magic Kingdom and Disney’s Animal Kingdom in a single day, but it requires a "Park Hopper" ticket and a very disciplined strategy. Because Animal Kingdom typically opens the earliest and closes the earliest of the four parks, the best approach is to start your day there at "rope drop" (official opening). You can usually experience the headliner attractions like Avatar Flight of Passage and Kilimanjaro Safaris by mid-morning. Around 1:00 PM or 2:00 PM, you would then transition to Magic Kingdom. Keep in mind that these two parks are located on opposite sides of the massive Disney World property, so the bus transfer or driving can take 30 to 45 minutes. Once at Magic Kingdom, you can stay until the late-night fireworks. To make this "two-park" day successful, using the Lightning Lane Multi Pass (formerly Genie+) is highly recommended to minimize wait times for popular rides. However, be prepared for an exhausting day; both parks are large and involve a significant amount of walking. Most families find that trying to "do it all" in both parks is impossible, so it is better to pick three or four "must-do" attractions at each park to ensure the day remains enjoyable rather than a stressful race against the clock.