Moving large groups of airs seems unnecessarily slow, the plane formations are much too spaced and when targets are nearby planes are too passive and don't attack fast enough. Does anyone disagree?
There is a bug where clicking too much will cause the planes to slow down and try to re-accelerate. It was fixed at one point i'm almost sure, but it seems to be back again with a vengeance for some time now. There are also bugs where hummingbirds will freeze when they patrol find ground units. Or freeze up when they attack into other hummingbirds. Kestrels will also freeze up instead of doing their normal strafe movement. Bombers also have issues with area attacks and picking targets, which results in them not doing correctly angled bombing runs and instead turning around really slow and being all weird. Basically, what you describe is mostly due to bugs I think.
Personally I wish planes, had some situational awareness so they require less micro. Sending a bomber to attack a mex and then watch it merrily bank right INTO the enemy base, instead of away from it, drives me crazy. With a bit of AI they could hopefully not be so suicidal. Not run into the bugs @elodea mentions but that is probably because I don't click at the speed of light like he does.