Falco is a pretty tough matchup. His lasers and reflector (provided the opponent can use them well) can both cripple the ability to approach effectively and throw pikmin from a distance. Also, he does far better in the air than olimar, and his spike is freakin deadly. One thing ive learned is to not go offstage against him, just calmly wait on the edge, because his phantasm is a predictable recovery that can be punished. He can typically be down throw'd twice in a row due to his fast falling at 0%, then follow that up with an usmash or combo of choice to rack up an early lead. However, he can also use his down throw about 3-4 times (depending on your DI skizzles) and get some damage up on you. And his bair is pretty fierce. Olimars whistle is not as good a strategy, as falcos attacks come out pretty fast, but if you predict them, punishment always tastes sweet.
So in summary:
Moves to watch out for:
dthrow, bair, dair, reflector, laser, fsmash (pretty good if it hits), usmash (same reason)
How to combat:
As with any unfavorable match-up, the easiest way to win is mindgaming. (something I have yet to master) Figure out your opponents bad habits or quirks and punish the hell out of them.
Sooooo yeah.
Tell me if ive said something incredibly stupid