Dropships:
Here's a brief description of the Spirit Dropship credited to Bungie.net:

TYPE-25 SPIRIT:
The Type-25 Troop Carrier (or T25 TC) is also known as the Spirit, although it is almost universally identified as troop carrier or dropship. It is capable of carrying up to 30 infantry and 2 vehicles. It is armed with one heavy plasma auto-cannon.

This map concept started as a general idea of building a Spirit Dropship (aesthetic map). I then thought wouldn't it be cool if I could create spawns inside the dropship in order to simulate the ship actually dropping troops into battle (still aesthetic)? Well eventually I expanded that idea even further to include not only one Spirit but a few smaller ones as well to simulate distance and an attack area for a larger playable space. Eventually the story and the map itself developed into this:

On a bright and sunny day on a distant world a UNSC beach defense base suddenly came under attack by the Covenant using Spirit dropships and heavy vehicles. The covenant were bent on nothing more than total annihilation of the immediate UNSC forces. They committed their best weapons and personnel immediately to the fight in order to quickly decimate the UNSC and wreak havoc on the planet. It seemed easy for them at first only having to conquer a relatively weak set of bunkers at the beach. However the Covenant quickly found out they had underestimated the UNSC forces when a larger defense base was discovered.

The Harbinger of Death Spirit dropship (Lower Port Aft view):

Above Front Port view:

Aft Starboard view:

Top view:

Beach invasion area with 2 other Spirit dropships:

Beach defense (Green Base):

Overview of larger main defense base:

Starting from left to right
Tank Depot (separate part of main Blue Base):

Red base (tactical and strategic):

Blue base (Vehicle Depots):

This map is intended to be a large vehicle based attack area with 2 opposing forces. The invading force is comprised of heavy, medium, and light vehicles both ground and air with limited specialty infantry (Special Forces). The defending force is comprised of heavy, medium and light vehicles both ground and air with limited specialty infantry (Special Forces). Both sides are fairly evenly matched but each can have different advantages over the other depending on skill, weapon choice, and vehicle matchups. Enjoy this map and if you want to see the progression check the map preview section for the same title.

Special thanks to FrankthaTank ST for all the help