Not sure if this is the right place, hopefully a moderator can move it where it belongs.

I realize this would only be possible day of departure, but is there a website where you can put in your airline and flight number to find out the planes registration number?

Then I would suspect it would be a different website where you could input a planes registration number to find out how many flights it has taken, it's age and other history. Is there a site like that as well?