Don't see it mentioned in this thread but Hunter Killer's only target enemys in thier line of sight, so if on the map its not facing your general direction you are safe for a while until it turns, you can then hide in cover for the 5-10s it takes to go back out of LoS area and you can proceed.
I get killed by about 5% of the Hunter Killers that get called in, and maybe only 1-2% of the ones that go into the sky following this strategy.
I already mentioned that this isn't true. Although I don't have any video proof I can offer anecdotal data that the Hunter Killer has targeted me even when it wasn't facing my direction.
This is one reason why I don't like them. They are not predictable. They will literally "turn on a dime" and go right for you, even if they are facing a different direction. It's ridiculous. These killstreaks are dumb, and they don't belong in COD. Just like Lightning Strike doesn't belong in COD /semi-off topic.
Mine always go for uav's even had one I threw at a sniper literally aimed right at him he qs'd me I thought at least I'd get revenge instead up pops blackout I nearly cried. Also thrown one up in the air and it proceeded to do a prompt 180 and dive bomb a guy sneaking up on me which would have been nice if it saved me but alas mistakes were made.