Some valid answers are already given by other commentators. Just want to highlight that commercial airlines are operating barely cost positive. Every extra bit of cost added has to be at least covered by some other stream of revenue. How much more money can a seat in these crammed airliners make to cover the cost of R&Ding and maintaining additional safety measures?

According to the games it was China that started the Great War. In the TV series, they hinted at plans of VaulTec to profit off of their vaults with starting off the war with a first strike.