In a lot of maps I tend to put my units near the destination point (except when there is an obvious choke point early on that I can take advantage of) to give me more time to get unit points to place troops with. That doesn't work so well on this map (even though they are flying, the way they do it actually does make a pretty good choke point at the right once I had time to watch how they moved instead of frantically trying to drop troops to kill the final waves). I was able to regularly get 1* on it (which is what I had been doing), but with this it went from 1* to 3* pretty easily.