i was 20 weeks when i flew to Singapore and recently was 30 weeks pregnant and just got back to Switzerland (Singaporean living in Swiss). was a total of 18 hours including my transit time and connecting flight. most airlines will accept you as long you are below 36 weeks with a single uncomplicated pregnancy. however, above 28weeks, you need a letter from your gynae stating that you are safe to fly. before i fly out, i went to KKH. gynae checked me and baby and said i am fit to fly. SQ airlines actually didnt ask for that letter eventho i look like a whale. lol. for your covid concerns, continue wearing a mask, and often sanitise your hands and better gtt your booster shot if you have not.