What would be more fuel efficient though, a Spooky loitering or an Apache hovering? Also, does the Spooky have the laser lock ability of the Apache? I imagine it does, most modern ground attack aircraft do. I imagine the stand-off distance is greater in the Apache coupled with the Hellfire and Longbow systems...but, that being said, I ponder if a Spooky could use a targetting computer to fire a shell from stand-off distance and have it hit a target lasered by a forward observer.
I mean, Spooky usually needs to loiter at altitude and within visual (camera) distance of the target, the Apache can hide behind a hill and fire its Hellfires out of enemy AAA and SAM range and those Hellfires can hit their targets as required. Also, I'm not sure about the on board electronics of the Spooky, but I know the Apache can use its Longbow radar and peek over hilltops and tree lines to paint the enemy (as can the Kiowa IIRC, only that can also use its camera and lase targets whilst hiding behind hills and trees) and then send a multitude of Hellfires over the hill top to meet them. Admittedly though, the cost per Hellfire versus the cost of an artillery shell, it's a completely different magnitude.
I guess, really, what it boils down to is different applications for each platform, the Spooky is, quite literally the artillery, an area affect weapon, whereas the Apache is more like a sniper, a precise long range killing machine. Honestly, for the kind of warfare we're in now, a Spooky will do just fine, an Apache is a bit like the F-35, overkill and overpriced for desert counter-insurgency operations. But the Apache has her role, and as we drift into Cold War II: Cold Harder, she'll be back in Europe where she belongs.
(Note: All statements are the written confessions of an Apache fanboy and as such may contain trace elements of bias and AGM-114)