Before you start dreaming of gameplay inspired by the animated film Valiant (2005), we can assure you that playing as a pigeon in Battlefield 1 is pretty much a short change of pace in the campaign. You will, however, get to steer the bird slightly for the period it's in the air. Not quite IL-2 Sturmovik, but it sounds interesting nonetheless, even if it doesn't carry any mounted machine guns or dive bombs.
Spoiler alert: Those of you who don't want to know anything else should stop reading, because below we describe the setting.
In one of the campaign missions you'll drive a tank. At one point you'll get stuck in mud, and the tank will get jumped by enemy troops. In a last, dramatic, desperate attempt to survive you'll send out a messenger pigeon with coordinates of your location to command, so that they can give supporting fire with mortars. Are you exciting to jump in the pigeon pilot seat?