From Conflict of Nations Wiki
Aircraft equipped to detect and engage submarines and surface vessels with torpedoes and guided missiles. These units are also able to reveal submarines and navy officers from the first tier, and can carry missiles towards later upgrades.
Bombers excel at attacking ground targets, particularly buildings and fortifications which in turn affect the population and ergo resource income. Stacked units are also very susceptible to heavy damage. These air units are able to carry and launch cruise missiles. Later tiers are able to bypass bunker defence bonuses.
These bombers also have the benefit of having stealth when not in combat, and not declaring war when infiltrating enemy airspace.