To answer the question of what has taken the place of air travel, domestic within as well as international mass transport to and from Ukraine has been predominantly train based during the most recent invasion:

https://apnews.com/article/russia-ukraine-war-riding-the-rai...

https://apnews.com/article/poland-railway-disruptions-arrest...

No flights at all. See it yourself https://www.flightradar24.com/