Some huge planes(Mostly bombers) have these cannons to the side that fire huge explosive bullets that release Wind-Spread Vapor that spread in different areas upon ignition, they explode in mid-air and release the vapor. In Blockland they will probably explode 32 1x1 bricks up, then, after 3-5 seconds it turns into fire, flaming the whole area.
I wish we had some cannon tool that can do that, the reason why I say "Only usable in V's" is because they have special artillery cannons that can do that,too. It'll be awesome if we can use it in tanks, planes, boats, etc.
And they're just perfect for dogfights, when it comes to carriers or ground, its awesome.