I'm in favor of this.

Since we can't change how AE works I think a way of doing this would be by creating a world that does only allow real world airlines, however, while also removing political restrictions (which will allow fifth freedom routes), but enforcing terminal and gate leasement restrictions. Let's say 10 hubs only and only 5 terminals and else a max of 5 gates in ones country and 2 or 3 gates in other countries.

This would allow Routes like the old PanAm Around the World route or fifth freedom flights from Europe to Australia via Singapore for example.

The rule would be that spamlines wouldn't be allowed in the world and that a realistic approach to building the airlines is encouraged. It'd work on a the principle of good faith that players will follow the rules, but if there is a suspected person we could present the case to a moderator or a gremium which would decide on a case to case basis if the accusations are warranted and then remove and block said player from this world.

On the other hand we could also create a world to which you'd have to be admitted in to.

All this addition of the world would do is create another world for players that would like to have a more realistic approach to the game, while not banning anybody from the already existing ones.

200 million? depends on the airline's size: I would be either investing in growing my airline with leases, if the airline already is at the size that I like it to be (100-300 aircraft, I prefer building quality airlines with some realism in contrary to spamliners) I start buying the aircraft, start investing in marketing, pay raises to get my reputation up to 100 and then save up to the necessary few billions to buy the replacement aircraft to not be dependant on leasing anymore. And that's basically it. Sometimes I build a little regional airline with a mini hub in the country, but apart from that after that the game get's pretty boring as there is no management required anymore.

I used to introduce ZRH-AKL in a premium heavy B747SP and later in a B772LR.