Flight arrows (APG p.176, http://paizo.com/pathfinderRPG/prd/advanced/advancedGear.html)
"These arrows have light shafts and special fletchings to give them greater range. A flight arrow's range increment is 20 feet greater with longbows, 10 feet greater with shortbows. They deal damage as if one size category smaller."
Equipping Flight Arrows as "contained" by a bow do not adjust the bow's range or damage, although they show listed as its ammunition.
For that matter, neither do "Iron-tipped Distance" arrows (UC p.130 http://paizo.com/pathfinderRPG/prd/ultimateCombat/combat/easternArmorAndWeapons.html) adjust damage (-1) or range (+10')
Pathfinder core supplements