I spent a few hours to check for missing airports in India, Pakistan and Russia. Found quite a few, including such big airports like new Moscow international (Zhukovsky), Cherepovets, Bovanenkovo or Sabetta, with more then 100k pax/year regular scheduled services. Most are however in the small regional 50k pax/year and less category, but would still be very useful to game. I submitted the list to support, lets hope they will accept it.
Support will need reliable data sources. You have also included charter flights; these flight do not count.
I used the russian state registry for russian airports in russian language, official russian state air transport ministry website, http://www.favt.ru/dejatelnost-ajeroporty-i-ajerodromy-reestr-grajdanskih-ajerodromov-rf/
I also cross checked data in airline schedules, wikipedia and airport operator websites. There are also statistical data on pax, post and cargo on the ministry website (see RTFs linked below) http://www.favt.ru/dejatelnost-ajeroporty-i-ajerodromy-osnovnie-proizvodstvennie-pokazateli-aeroportov-obyom-perevoz/
For India, I mainly used Wikipedia, but cross checked the data on AAI website.
Another missing airport is TCC - Tucumcari NM.
Zhukovsky/ZIA airport in Moscow is still missing, and actually has quite a lot of traffic in real life
New/missing airports that have been reported to AS Support should make it into the game when we start the demand. That should hopefully happen within a few months, it’s in our plan for 2Q2019.