A bomber is a flying machine that is used to drop bombs on targets. Most function like helicopters, using a combination of balloons and propellers to position themselves above their target. Bombers can also be in the form of a plane, though those are more challenging to create.
Bombers can be used to pass most levels that have destruction related objectives, given that they are carrying sufficient weaponry.
Most bombers use grabbers to release their payload, as it is the easiest system to create. The grabbers can also be used to pick up other light objects afterwards. Every bomb dropped needs to be balanced by releasing a balloon / propeller of respected buoyancy.
Balloons are used to offset the bombers "dead weight", allowing it to float. Propellers are used manipulate and move the craft.
Bombers suffer from two main issues. Aside from being sometimes difficult to create, their explosive payload is often exposed meaning they can be blown up by stray arrows or debris. Similarly the balloons can be popped causing the craft to lose buoyancy and crash.