Answer: UFO

UFO stands for Unidentified Flying Object. It refers to any object or phenomenon that is seen flying in the sky but cannot be identified as a familiar or known aircraft or object. In popular culture, UFOs are often associated with the idea of extraterrestrial spacecraft or alien visitors. So, in the context of the clue "Alien's ride, for short," UFO would refer to an extraterrestrial spacecraft.

Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: What a high-altitude balloon might be mistaken for. Explanations are generated by AI and may be inaccurate.