Along with TSA numbers improving, signs of cities starting to reopen, and Modernas promising results on phase 1 vaccine trials.
FRA and LHR I believe are cago routes. Passenger traffic may not increase until they figure out how to detect CV19 passengers. I believe passengers will have to self quarantine for 2 weeks upon arrival and theres a substantial monetary fine (>$1000) in the UK if caught breaking the 2 weeks quarantine.