At least once during the course of a day, I will be outside, look up, and wonder what aircraft that is flying over my head at altitude. Now, I know there are good tracking sites that tell me what flight it is, but I have seen some folks post to this site as to what the tail number of the particular aircraft is.
My question is twofold:
1. What site do you use to tell you what the tail number is of a particular flight?
2. Is there a different site that shows information for flights outside the US (I'm looking to travel abroad in the next couple of months), or does the answer to the first question answer this one?
Thanks for the help!