I use both of these characters, so I guess I can give this a whirl.
From Falcon's end, your big advantage is your mobility. Robin's mobility compared to falcon's is relatively crap. And like every matchup, you are amazing at juggling them. Robin, like marth and lucina, has weaker options for dealing with people below them. Down air is really laggy, nair only covers their sides, and even though elwind will almost always stop you if they use it, it puts them in an even worse spot 90% of the time because they are now free falling from an even higher altitude.
That being said, Robin has a ton of options when it comes to stopping approaching and punishing you. Its really hard to approach a smart Robin head on, as they have a ton of options. As robin, I can use elthunder or higher to stop you, arcfire stops everything you have, and reverse ftilt is fast and relatively safe. More robins need to use their ftilts/dtilts more; really fast moves. Where you have watch out for Robin the most is offstage. Robin wins pretty handily offstage imo. Besides being able to projectile spam you from onstage, Robin's fair has more range than knee Im pretty sure, and Robins upair is amazing (not as good at juggling as falcons, but way stronger and an even bigger hitbox). If robins going for an upair, you have to bait it out early, because it has a good amount of end lag. Lastly, watch out for elwind spikes. If you try to go low as falcon, there's not much you can do to stop it besides timing an upair perfectly. I need to play the matchup more as falcon (The other good player here is a Robin main), but it comes down to
focusing your approaches from above or behind, and keeping robin airborne. Robin wins head on and offstage.
If I had to put a ratio on it this early, I'd say 60:40 robin's advantage. I need to see more tourney levels versions of this matchup though to be sure.