Today I created a new tag, plane-spotting for my question about identifying aircrafts and flights. Are these kind of questions in the scope of Travel SE?
IMO, they aren't. These are not practical, travel-related questions. For more advice on this from our overlords, read Let's Play The Guessing Game on Stackoverflow Blog. I know we have an
identify-this tag but that can still be somewhat practical in the sense it allows you to identify monuments and landmarks when visiting some place. Identifying aircraft on the other hand is pure guessing game that doesn't benefit anyone practically.