You're not going to find a real answer to Pit's arrows when playing against a good Pit. Your best bet is to fight in spite of them. Make sure to Powershield any arrows coming from the front, and keep an eye out for tactical arrow strikes from the other sides of the screen. Falco's reflector shouldn't be used excessively against a decent Pit. It's kind of hard to explain but I'll give it a go.
When fighting a Falco, Pit's biggest strength is altering the pace of the game. By reflecting arrows Falco comes to a stop and leaves himself open from the top and behind. This might not sound like a big deal, but to a Pit who is a good deal away from Falco, this will lead into an Arrow Chase.
Gah, I can already tell that I'm all over the place in my description. I'll reiterate.
Pit can change the direction of his arrow at the last moment and avoid having the arrow be reflected back at him. A good Pit can also control Arrow Loops while fighting. With this in mind, Falco's reflector is just a slower shield that lags him considerably. However, Falco can still do what any other character can do. Powershield and Shield Dash. When Shield Dashing properly you don't lose much momentum in your run and thereby keep the pace of the match in your hands.
And luckily for Pit, he can survive Falco's Chaingrab to Dair on most stages. But it still does nearly fifty damage to him at it's maximum if I remember correctly.
But in the end, Falco has the advantage in this match-up. Though in my opinion it's a closer match then most of Falco's other match-ups.
Final thought; keep in mind I'm referencing good Pit players. I've only seen three or four that can actually do what I mentioned in this post.