This is one of my most played matchups with Rob. I personally think this matchup is even. Falco can camp the crap out of you, but Rob has the tools to stop it. Rob gives Falco a hard time phantasming away with his large range and so on. Many players tend to think this is Rob's worts MU because Falco outcamps you. Many seem to forgot that Rob actually has a really good offensive moveset too. With his large range, Rob wins the hand to hand combat. The scariest thing in this MU is his Jab, it's hard to get through a well placed one.
You don't even have to be afraid of his chain grab, it only works until 18% and then you can just jump away and fair. One thing to watch out is his gatling combo. If you are no careful, it will easily shield stab you into death. He can also dair spike you to stall you out of fuel, but our Uair wins Falco's dair.
When the fight gets offstage, Rob is gonna enjoy it. When Falco reaches the ledge level, where he must phantasm, go for the ledge, and ledge drop bair, it's pretty good at keeping him away for a long time. It's hard to actually gimp a good Falco, but he will eventually die this way.
Rob should die to Usmash only. His fsmash kills you at stupid high percents with good DI. Avoid that usmash at all costs. Ftilt is still as godly as ever in this MU, when you are at ftilt distance, he has a hard time lasering, but can only do shine to beat it, which is very punishable.
What makes this MU is the stage. On a stage like battlefield, this is even. On stages like FD, you gonna get pwnd, ban it. If you pick Frigate, you win. Take full advantage of all the Falco's bad stages. I would even take Falco to Brinstar. I have played a lot in there and in this MU, the stage doesn't hurt Rob at all, but destroys everything Falco has.
In the air, you gotta watch out for his bair, that is all. If you can land a hit in the air in front of him, he is easy to combo due to his garbage fair. When you get juggled, move offstage and recover with your upB, Falco's uair can kill Rob early thanks to his negative falling speed.
Don't get annoyed by laser camping, learn to powershield them and they won't be a problem. When you slowly approach Falco and he phantasms away, if the situation is too good for Falco, don't try to punish it, repeat the same process. Also, you can pivot grab Falco out of his phantasm.
Remember your projectiles, when you get Falco offstage, you are free to spam. Always try to charge your gyro. Use it when Falco phantasm. It will kill Falco early, if it doesn't your fully charged laser does the rest.
Overall, you win in the air and ground, but Falco is still a trouble to approach and kill, so the MU is even to me.
My post is pretty disorganized, but hopefully it will be of help.