Oh, most wise and sagacious Agimimnon, possessor of the legendary +5 tongueof biting sarcasm known only as Sardonis, I come humbly into your mostdivine and erudite presence, bearing a question beyond the abilities of allbut the most scholarly, astute and single-minded of sages. Not without reason would I disturb your eons of study, but within the D&Dfamily I am so proud a member of a dilemma of most gargantuan proportionshas reared its ugly head, and even the encyclopaedic knowledge of our ownsage and DM has proved unworthy and incapable. Were I of the proclivity to do so, I would let such a trivial issue fallgently by the wayside, as do the bodies of our party's enemies, but boldlydo I bring this matter before you, divine Agimimnon, in the hope that thyblessed wisdom, the stuff of sagas, may dissolve the quandary in its radiantglory.

This modest enigma do I pose, my very character and all his worldly goodsriding on the result, hoping beyond hope that within the avalanche ofpointed remarks and derisive procrastination I may find a gem of wisdom, andthus the answer that I seek. The question is this: Under normal circumstances, would a flying creaturemaking a Flyby Attack as the feat (MM, pg. 11) suffer an AoO from acharacter it is attacking, who is on the ground at the time? Though it wouldseem obvious that an AoO would occur, the feat suffers from a remarkableparallel to the Spring Attack feat, in which no AoO is received by themoving character/monster, and it is this similarity which has provoked ourconfusion.

As with so many other perceptive questions, my dear reader, this one is notanswered by simple logical parsing of the rules texts. A less patient rulesauthority might respond with a curmudgeonly "If it ain't stated, it ain'timplied", but I thought I might recognize the diligent eloquence in yourrequest by responding with a carefully analyzed reply. When all else ispeeled away, the essentia of my answer will be "this issue is open to DMinterpretation, but here's my opinion".

There are actually three feats listed in the core rules that deal with theMove, Act, Move phenomena: Flyby Attack, Ride-by Attack, and Spring Attack.Each contains slight semantic differences from the others.

Spring Attack is the most straightforward of the three feats. With SpringAttack, the character may move, attack, and then finish his movement. SinceI get reams of whiny rules-lawyering emails asking me to approve oneparticular abuse or another, I will take a little time to clarify this feat.Spring Attack DOES NOT allow your munchy-special to move more than hisnormal speed or make more than one attack, even if it is used in conjunctionwith the jump skill, as if that makes some sort of distinction. The nextperson to ask a stupid question about this feat is going to need amicroprocessor to reroute his basic biological function of wasteelimination, because I'm going to give him a few new holes to choose from.Am I clear on this? Good. Now let me spell out the exact effects of SpringAttack: the feat is used as a special case of the move + attack action.During the round, you may move part of your speed, make a single attack as astandard action, then finish the rest of your character's movement. In nocase may you move more than your speed, attack more than once, or performany action other than a single attack. Fortunately, Spring Attack protectsyou from Attacks of Opportunity that your movement might normally provokefrom the target of your attack.

Ride-by Attack is perhaps slightly more complicated than Spring Attack.This second feat is a special case of the charge action. All the normalrules for charge apply, and the character must be mounted. Do not make meexplicitly list each restriction and benefit of the charge action, youshould all already know what they are. Ride-by Attack allows the characterto split his movement, which must be in a straight line but may be up toTWICE the mount's speed as per the rules for charging. Like SpringAttack, a character using Ride-by Attack is protected from Attacks ofOpportunity that his movement might normally elicit from the defender.

Flyby Attack is the most versatile of the three feats. An observant playerwill note that Flyby Attack allows the acting creature or character toperform any "partial action" at any point during his move. The text hereshould read "standard action", but that's not really at issue here. Thedistance moved is governed by the flight rules, so a diving flyer canactually move more than his fly speed in a turn and use this feat; again,this is not the central concern. The clause protecting the possessor ofthis feat from Attacks of Opportunity is missing from the text of FlybyAttack. There are two ways to interpret this omission: (1.) the protectionwas not intended for this feat since it is inherently more powerful than theother two, or (2.) it was accidentally excluded since even game designersare fallible human beings.

Now, since my opinion has been requested, it shall be given. I like thefirst option; the protection clause was not included because of theversatility of the feat. A dragon with Flyby Attack, for instance, mightfly within range, cast a spell, and then veer back out of range using thisfeat. Also protecting the scaly terrors of D&D from opportunistic strikeswhile they sweep in for a strafing run may be too much power for the scopeof a single feat.

As always, your DM's word is best described as law.

-Agimimnon the Great, Bearer of Sardonis, Wise Enough to Use It Only whenNecessary