This is pretty close to what's already implemented, except currently the cost per family does not depend on the number of families operated.

I understand that there is a base cost for each family is already implemented that's what makes this idea easy to add to the game. Instead of changing entire code to slow constant expansion, I am for ideas that add to the current code. This for one can be done fairly quickly and second it also makes your work on the code less tedious.    

For something that I think would be easy to implement would be with Aircraft maintenance.  Make it more expensive to have Multiple families and or manufacturers of aircraft. If you think about it, tools and staff training on different systems have a huge cost to the airlines,  An example would be Base cost for 1 family would be Base X 1, for 2 families Base X 2 and so on. so the more families you have the higher the Base cost would be for each family. Then have another multiplier for Manufacturers. To give you a better idea I will put numbers to the Families

                                                                       M=Manufacturer    F=Family

Manufacturer A, Family A = 2 mil                 So just having MAFA would have a base cost of 1 X MAFA(2)= 2mil

Manufacturer A, Family B = 2 mil                 Having MAFA & MAFB would be 2 X MAFA + 2 X MAFB) =8 MIL

Manufacturer A, Family C = 2 mil                 Having one M and 3 F would be  3 X MAFA + 3 X MAFB + 3 X MAFC=  18 MIL

Manufacturer B, Family A = 2 mil                 If you had more than one manufacture it would look somthing like this

Manufacturer B, Family B = 2 mil                 2 X (4 X MAFA + 4 X MAFB + 4 X MAFC + 4 X MBFA) =

Manufacturer B, Family C = 2 mil                 2 X (4X       2    +4 X      2    + 4 X    2     + 4 X     2    ) = 64 mil

It could be coded fairly simple.

=Count(Manufacturer A: Manufacturer Z) * (Count(Family Base cost A:Family Base cost Z)*Family A)

This would be the basic formula for each family that an airline had.  As a result, airlines would be penalized for multiple families and manufacturers. It would be interesting to test this in one of the worlds as it would slow the growth of airlines by quiet a bit.  Do I think this approach adds realism to the game? Yes and no. I think having every family of aircraft ordered is unrealistic and this would penalize this practice by quite a bit.   R5 currently has 24 manufacturers and  41 different families. I don't think anyone could afford at least 24 *41 * base cost for each family. The boeing 747 family base cost would be 9,840,000,000 alone per month.  I know this may be a little excessive but I think the concept would work.  I know a lot of this pry doesn't make sense to anyone but its late and I am tired.  Feel free to rip it a part and critic it. Comments good or bad are appreciated(about the idea. )

Cheers,

Lurch 

So will these aircraft be (are?) used in any world or do we have to wait for new earlier start worlds?

It all depends on their production period. For example, the Antonov An-2 has production from 1947 to 1991. so any game world that starts before 1991 will have that aircraft available until 1991.  That is just one example but if the production period ends be for the start date of a world than the aircraft is not available.

If someone could help Uruk out with all the aircraft on AE I think that would help. I couldn't find it for the life of me and it is probably somewhere simple. lol

Spying has been happening for decades, it is nothing new. What has changed is that the technology has improved, making it easier for countries and/or groups to do it.  I am not happy that spying is done on citizens but I do not think that it will be stopped. If we close one way of spying another will open.  I have to think that this might not be a scandal at all but a plan to get it out there that the US can do this and has been doing it for years.  I say this because if terrorist groups know that it is happening, it could deter them from using any technology to communicate with each other making it much harder for anything to be carried out.  But I am a person that looks at all aspects of a case to try and see the positive and negative impact that it could have.

Just my 2 cents.

As far as I know there is no current function that lists the airports showing the pax demand but typically the higher the gate cost, the higher the pax demand.