I think it would make it more interesting to be able to own individual  properties. For example each gambling property can be owned and profits go to that person...if that person is killed the property goes to the owner etc. Same with airports.

Airports are it own thing in the game? o.o

...?

Casino's can be owned, profits do go to the owner. If the owner dies the ownership is forfeited, which takes money out of the game which keeps things better balanced than simply passing on to another owner.

I can't see any game benefits in allowing airports to be user owned. There's no risk/reward there and no game mechanic benefit I can think of to having them user owned. They'd simply pump additional money back into user hands, so inflating the economy with no checks or balances to warrant that additional income. 

Eventually we'll likely get back some form of the MR Stock Exchange, I'm hoping.

I'd enjoy seeing some territory-control elements added to the game. Setting up some kind of business rackets would be really cool. Airports are a bad implementation of that idea, as you're making an integral game feature reliant on player benevolence. It's like selling guns- you can't make certain features out of reach of any player simply because other players choose so. That attitude has never been supported by the admins or the userbase.

In support of the original idea, I think setting up NPC properties like DFPs would be very cool. Make it more involved than just tipping the FBN and you could have a very engaging and rewarding mid-game feature on your hands. Balancing the risk/reward wouldn't be too tough, either.