help in ID of mil choppers

I live under the approach of traffic heading toward McGuire / Lakehurst. ( 20 miles out).

Recently three choppers flying in single-file formation flew over during the evening.

The only visible lighting on them were three aqua colored non-flashing lights.
The three lights were in a straight line front to back.
Pretty much evenly spaced.

Any ideas on the type of bird these were ?

thanks, jack