Airport unlocks Tokyo, London and Paris towns. So unlock if you want the look of these. Tokyo towers do have the highest capacity but will take longer to build.
Disasters gets you keys which you can use for specialisations. That will grow your city quicker. You have to spend $$$ to make disasters easier to complete is the downside.
So the choice is based on your goal. Prettier - airport. Grow population - disasters. High groeth (for coins) then both.
Bear in mind that you one day HAVE to get the airport at some point and later on in the game 100k coins is easier to get. I get 24,000 coins a day now (1.7m population) , but getting to 15,000 is a nice level (about 160,000 population).
@kunderaz said, "You have to spend $$$ to make disasters easier to complete is the downside. "
Based on what do you say this? I find completing Vu disasters no different than upgrading buildings and don't cost anything at all if you just make what you need.
