Dieselpunk mech action in Iron Harvest (opens in new tab) will get a bit more truth, justice, and the American Way later this month as the Operation Eagle expansion releases on May 27th. The new DLC brings an all new faction, The American Union of Usonia, and their emphasis on air power to the battlefield. Of course this isn't just normal air power with planes or something, this is giant flying airships. The new American hero, Admiral Mason, apparently has a flying "colossal battleship" and I won't lie to you I am excited about that.
The DLC will focus on a campaign for the new faction, playable in singleplayer or co-op, with 7 missions and 25 minutes of new cinematics. That's good to hear, since the singleplayer and cinematics were the best part of the main game. The introduction of air power also includes new units for every faction and paratroopers who can drop behind enemy lines.
The DLC will also include "New playable allies from a yet to be revealed secret faction." Given the history of the world of 1920+ revealed in past games, that might be a group like the Nordic Kingdoms, Crimean Khanate, or Clan Albion. We'll see later this month.