First change I would suggest is to have some kind of avatar representing the player on the screen. This allows players to identify more strongly with the game.
Second, reward and punish. Add some kind of consequence, perhaps even a game-over state. You can make this easy to avoid but it requires constant attention. Reward. Coins are your "health" not exactly a reward since you need them to continue playing, but add some random rewards (this is primarily where the addiction mechanic comes from). Big, rare rewards make games addicting.
Going further, you might want to add a set-collecting mechanic. Try playing "Ticket to Ride" and see if you could adapt some of those mechanics to your game.
Finally, the interface is not very game-like. It doesn't look like a game.
Avatar? Could do, but it might feel weird since there are no other avatars to interact with.
Here's an idea: You start out as an avatar of someone looking shabby and poor. Like, broken shoes and dirty t-shirt. As you progress you start looking smarter and smarter. Eventually you travel in a suit with a businessman looking little hand-luggage. I'd have to get graphical to pull that off which is not something I'm good at.
Yes, the interface needs to be improved. It's hard to make something cute without Photoshop skills. I'd happily pay someone if I had the time to organize and I knew the results would be decent.
Coins are the primary thing you spend time earning in this game, yet the number and icon for them is tiny. They should be pumped up and thrown in my face to let me know just how rich I am. (In general the interface isn't as game-like as it could be, but that's hard to solve if you're not good at that sort've stuff). Other indicators of how my standing is improving would be nice too. Perhaps show a picture of the plane I'll be flying in before I fly away, and upgrade it over time?
And when I do finally get a bunch of coins, I just spend it all to go somewhere else and earn more coins. There's progression in the form of traveling, but locations are differentiated enough for me to even notice. Kingdom of Loathing is a good example of some things that might work: instead of having a list of tasks, have me click on the map. Make me know exactly where I am in the world.
I've suggested this before, but I still think adding clearly defined tiers of travel will make good goals to drive the player. Tier 1 would be local jobs in your town, tier 2 could be the county, tier 3 would be the state/province, tier 4 would be countries, and tier 5 would end with you buying a flight to the Moon. :D
I only clicked around the game for a few minutes, but I have two general ideas: (partially borrowed from the Zynga Handbook of Doom, but you did ask for addictive...)
* Don't have players start with zero coins; give us enough to start off and do something fun or cool (i.e. book one flight, get to a new city), and then lead players into the game's job mechanic.
* It's a terribly silly (and transparent) game mechanic, but I love games with Achivements / Medals / Awards. Either make them all available from the start or (a la many iPhone games) only "assign" three achivements at a time, each with a certain "star" value; get enough stars and you "level up", which comes with a hefty coin bonus. This way, once players have figured out the game's mechanics, they'll continue playing for achivements (and you can use achivements to encourage experimentation with other game features).
The game starts with the tutorial. You answer three really simple questions and they all give out lots of coins. So, very soon you're on your way somewhere with your coins.
I am working on a "Awards" feature. What I think I will do then is to combine that with big rewards. And the awards should be awarded to you just by playing. You'll have to really work hard. For example, getting 100% on the questions under a certain time.
1: It doesn't feel like I'm playing a game as much as I'm clicking through menues. Make it more interactive, playful. Try to make the map a bigger part of the game, maybe having a flight-icon above the actual airport, and have a smaller "bubble" pop up with connecting flights, maybe try to display the target airport on the map as well.
2: Try to get coins to be a bigger part of the UI then it is. Actually, as joeld42 pointed out, the UI needs to be a tad more refined overall.
3: Achievements. Which you can share throughout the interwebs. Miles traveled are an excellent point system, make sure players can't cheat their way to lots of traveled miles, and use it to rank players.
4: If and where possible, add pictures to questions like BackPacker did.
Find a way to tie in some element of strategy. Think about how Empire Builder works with regards to transporting goods or something alone those lines. I'm just not really seeing the point in playing, other than it has unique feel, but no point. Give me something to go after to win....conquer....
Good point but... What? So far, the only skill is to know stuff and know it quickly. I was thinking about somehow incorporating that you race against other players somehow. Then, somehow you could use strategy to try to be smart and swift or just hard working and active. Haven't come up with something definitive yet.
Having reached out like this, it turns out that a number of people have hit bugs. I've received all tracebacks by email and will work on it this weekend.
I would love to build something with PhoneGap or something similar. Just limited time. Building something like that would mean having to more or less re-write the backend as a front-end data store.
In fact, there is a mobile responsive design thing at http://aroundtheworldgame.com/mobile/ which works OK in iphone/ipad but it's far from perfect.
Second, reward and punish. Add some kind of consequence, perhaps even a game-over state. You can make this easy to avoid but it requires constant attention. Reward. Coins are your "health" not exactly a reward since you need them to continue playing, but add some random rewards (this is primarily where the addiction mechanic comes from). Big, rare rewards make games addicting.
Going further, you might want to add a set-collecting mechanic. Try playing "Ticket to Ride" and see if you could adapt some of those mechanics to your game.
Finally, the interface is not very game-like. It doesn't look like a game.