First, you have to design the flight path of the gargoyles. Let's pretend that they swoop vertically downward, grab your guy, then take off.
They have average maneuverability and 60' speed. They do not have Flyby Attack, Improved Grab, Improved Grapple, or anything nice like that.
Starting 45' off the ground, the gargoyles fly straight down toward a point 5' in front of the target PC. When they enter that square, they then each burn 10' more of movement turning in place from straight down to straight level. They then move 5' forward to enter the PC's space (well, let's assume that the spaces are offset so that they can be side-by-side and do this) and initiate a grapple. Standard action to grab him.
Next round, they can fly away at half-speed at a 60 degree angle up. This means that a double move that round would put them about 50' off the ground and 30' horizontally away from the pickup point.
Now that we have settled flight path, you will have to decide things like awareness, surprise, etc. Yes, there are AoO for anyone who is not flat-footed (including the victim!). And yes, these are grapple checks. Note that if the PC (including gear) weighs more than 132 pounds, then the gargoyles will be pushed out of Light Load into Medium or even Heavy. I know that that will affect flight speed, but I don't know the rules about whether encumbered creatures can fly at all.
Assuming they can fly with a heavier load, and assuming the weight reduces their movement to 40', then a post-pickup double move would put them only 35' off the ground and 20' away horizontally.
EDIT: Doing this in a surprise round isn't really possible. Because they do not have Flyby Attack, they must conform to the move/std-action model. There will be a round boundary either before or after the grapple.
ANOTHER EDIT: Oh yes, mvincent is using the grapple rules. OK, so they can switch off on their standard/move actions to move the victim, like Gar1 uses std to move the victim while Gar2 uses move to keep up, then Gar 2 uses std to move the victim and Gar1 uses move to keep up. exhausting. And, of course, they are very slow. If they are encumbered, then they are only 15' off the ground and 10' over horizontally after one round of dragging away the victim. Hopefully you try this on someone Small, so that they can at least get 25'/15' away.