Night Stalkers

A music for a scene where a group of military helicopters move in the night using the cover of the dark flying low with lights off to avoid enemy detection

 

beginning perfectly encapsulates the vibe you're looking for, cant wait to see what else you do with these effects.
1:30 perfect melody, I do wish the melody pierced through the background a little better.
2:30 I feel like it would've developed the 1:30 melody a different way, rather than choosing a new melody. 
A good use of changing sounds for the melody, adds some good layers, especially when they overlap.