4. The Paladin
The Paladin is the plane from which Fourth Echelon operates, and in-between missions, players are able to take a break from all the killing (or not killing) and walk around it. There's a variety of things to do, such as talking to the crew members on board, checking mission stats, customising your loadout (though it's pretty dumb that the President restricts your budget so stringently despite the national crisis unfolding), and checking out multiplayer sessions. Though the game would have been perfectly functional without this flourish, it adds a little diversity and fluidity to proceedings, meaning that you get suitable downtime in between the intense missions, allowing you to cool off if need be.