That wasn't luck; that was skill. They reacted to your missile. Either you're in range of him and he can decloak you, or he has enough time to deflect, or is resource starved due to bad play or overburdened from you (unlikely given you're Prowler) or others (bingo), or he is actually not moving in a straight line which he shouldn't (a premise you ignored thus far). Especially not if you just rammed it already, or if you kept killing them. Like, hello anticipation? Heck, if you kept killing them then they shouldn't stick to Goliath.

I found the Mohawk much more suitable to kill Goliath. He can't deflect all the missiles, and if he does its just a matter of avoiding him enough. As long as you can aim you'll deplete his resources way faster than any other airplane can. I found it great in CTF (though not in FFA; although FFA doesn't interest me as much as CTF). I find FFA unrewarding because you can't compete on K/D radio and there doesn't seem to be some kind of goal (the bounty # just dampens your K/D ratio and seems to be have the purpose of a recent scoreboard). To me, FFA is practice for CTF/BTR. Ironically, a good enemy of Mohawk is a skilled Prowler who can anticipate movement and aim. Didn't see many of those around though.

Another observation is that the Mohawk is great to spray with the flame buff.

Its also funny how much more defensive people play in BTR. If they put in that effort during CTF and FFA I'd have a way more difficult time.