I've made a list of things that would improve the game, in my opinion, and start to get rid of Spamlines:
- Scheduling - When you create a route - you have to set times and aircraft, as well as days of the week. That way - putting a route on a plane takes longer and would slow down expansion. Flights that are departed at ridiculous times (such as midnight-6Am) will get less passengers because of their frustrating departure times.
- Maintenance - Similar to scheduling - you need to plan your A, B, C, and D checks for your plane instead of just getting the bill. You must then schedule them for times that the plane isn't on a route, of course.
- Hubs - Airlines should only be able to create routes from their HQ airport at the start of their existence. After they've existed for some time (90-270 days or something), they will be able to open a new hub. Then, they can depart flights from both of their hubs. Then, they have to wait another 90 days (These are all game days, btw) to open the third hub, and so on. This would limit expansion and prohibit empty hubs as some spamlines do (hubbing every single city that is a destination!)
- Used Aircraft Delivery - When an airline sells an A/C, it has to be delivered from the location of the airline, which would take time. Therefore, all Used aircraft purchases should have a delivery time of 24 hours for removal of the old airline's branding, then the flight time from the other airline's hub to your chosen delivery location. That way, Spamlines can't just buy the entire used market and create an instant 1000 plane fleet. Another suggestion in the used aircraft is that you should only be allowed to buy 2 or so used aircraft every game day - this also limits expansion.
- Finances - bonds should become loans - then you can pay them off ahead of time. Also, starting cash should be about 30 million for airlines in R worlds and 175 million for airlines in the sandboxes. That way - with my used aircraft suggestions and the like, you don't run out of money waiting for aircraft to be delivered
- Chronological considerations - Templehoff airport and many other airports in AE close at some point. Therefore - they should. For the example of THF, it should open in 1923 and close in 2008 in the game worlds. Then there is demand. Demand at THF was up until the late 70's when it began to dwindle. Rather than just have random demand changes, demand should change as time goes on in the realistic airports. This should also change based on time around the world - Air Travel was less popular, believe it or not, in the 60's than it is today, so there should be less demand all around then.
- New aircraft production - Aircraft should use production slots. This is when a delivery for each aircraft can be made once a day, once a week, etc. The manufacturer would give delivery slots to carriers, and so when a carrier orders a lot, say 50 737-700s, they get maybe every 3 production slots for their planes. Then, if someone else came along and ordered just 5, they would get a few in the middle of the other airline's slots. That way, spamlines don't kill production for others, and they allow for consistent and planned aircraft deliveries.
- Weight Variants - some aircraft offer additional MTOW packages for an added cost that increase the range without putting in different engines - these would work well as another option
- IFS Additions: Baggage fees, carry-on fees, boarding pass printing fees (Spirit does this!), iPads, premium Economy
- Essential Air Service and the like. In the USA, the government pays some airlines such as Mokulele and Boutique Air to operate routes that would be unprofitable otherwise, such as to remote airports in alaska, as well as remote airports in the plains of the US. Other countries have similar systems - I think this would be good for airlines looking to expand their networks. Cities with no demand (Teterboro, etc.) can have an EAS implemented where the airline will be paid to construct a terminal and start at least x number of flights to the airport.
In the end - these are just my suggestions that might not get implemented, but I think that they would help the game tremendously in becoming more playable and more fun!