I'm very new around here but downloaded the game last night and have been enjoying it a great deal. In the past I have played many of those browser based text games such as Planetarion etc which involved several thousand people all taking control of a planet/kingdom/army etc and fighting against other people. After spending a few hours playing airships it occurred to me that this game could have huge potential as an MMO following the same formula.
Basically, the game would be played over the course of several weeks and would involve everyone playing on a single map (or a group of maps depending server demand) the action would take place during 30 minute ticks, you would need to build defensive and attacking structures and fleets much like now although you would need to rely on AI to control your fleets when you are not there, you would be notified on when you will be attacked and you would need to arrange defense between your allies. The obvious differences are that flight time between locations and construction time would need to be hours and not seconds, this gives both attackers and defenders time to analyze the situation. There would also need to be another way to acquire resources asides from overtaking peoples cities. Obviously there are a lot of things to consider and this is only my half baked thoughts but in theory if done well and all little obstacles are overcome, it could make for a really interesting and exciting MMORTS experience. Imagine coming home from work one day to discover you have several enemy fleets incoming, only to have your allies band together and intercept the enemy on route and crush them out of the sky then you all create an attacking fleet to crush the enemy base in retaliation.
My theory is that some of the game play could be done within a browser (arranging attacks, defensive fleets, and building vessels) while everything else is done withing the game client, such as designing ships and defense, then people could play most things on the move or at work etc, while many battles could be fought in real time, mostly against an AI but sometimes against the enemy themselves (depending on whether they want to command the defense/assault themselves) Oftentimes the battles will be AI vs AI and will allow the players from either side to "watch" a replay of the action, this would of course need to be done server-side.
If your city gets taken over then you're either forced back to your nearest city, or you are destroyed and are then allocated a new city near the edge of the procedurally generated map with some extra money etc depending on how well you did before you died.
Anyway, just thought I'd stick that out there and welcome myself at the same time. Let me know what you think, Personally I think there would be a lot of difficulties to overcome but the end result could be epic :D